Amendment for clay soil

How to correct clay soils

When building new gardens it’s the perfect time to prepare the soil, and if you have clay soils, it is very important to build up the soil before planting.
Clay soils are usually very slow draining, and stick together in clods when wet. If they dry out, they crack and go as hard as bricks. If clay soils are left as they are, they can be a problem to grow plants in, but on a good note, clay soils are very rich in nutrients, they just require good preparation before planting.
To successfully grow plants in clay soils it’s important to both build up the soil with good organic matter and break up the clay with special additives.
The first step is to add gypsum to the soil. Apply gypsum at 1 kilo per square metre, digging this into the top 10-15cm well. Gypsum works on the clay, breaking it up into small crumbly pieces making it easier to work with and also improves drainage. If the soil is a very heavy clay, then this may need to be done more than once.
The next step is to build up the soil with plenty of organic matter. Do this by digging in large quantities of Searles Premium Organic Compost. Spread the compost over the soil at about 5-6cm deep and turn this in with a fork to approximately 10cm deep. This may seem like a lot, but the results will be wonderful.
This added Searles Premium Organic Compost will improve soil fertility and help break up the soil, preventing it from drying hard like a brick. Now leave the soil undisturbed for a few weeks to settle and to allow the soil structure to change now with the addition of both the Gypsum and the compost.
If you are planting Australian Native plants, build up the soil with Searles Native Plants Specialty Mix. This mix contains all the right nutrient balance for their low phosphorus growing needs.
Before planting, give it a good turn with a fork and now you will see a world of difference. The soil should be far easier to turn and work and it should have a crumb-like soil texture. This is now ready to plant into. If you are growing seasonal crops such as vegetables or annual flowers, you will have the added advantage of being able to add more gypsum and compost again after each season.
Clay soils can be very rewarding and tend to grow excellent crops, given the right treatment. By constantly adding more organic matter year by year and mulching well, the soil will naturally improve and the benefits are enormous.

Many Australian Natives can tolerate clay soils. Here is a list of Australian Natives and other plants suitable for clay soils.
• Callistemons (bottlebrushes)
• Melaleucas
• Some banksias such as B. spinulosa varieties and B. ericifolia
• Leptospermum ‘Pink Cascade’
• Spotted emu bush – Eremophila maculata
• Westringia fruticosa – Native Rosemary
• Asters
• Daylilies
• Coreopsis
• Grevilleas such as Grevillea ‘Poorinda Royal Mantle’, ‘Moonlight’, Honey Gem’
• Brachyscome multifida ‘Cut-Leafed Daisy’
• Scaveola ‘Fan Flower’
• Dianella – Flax Lily
• Pandorea
So remember, to prepare clay soils:

  • Add gypsum at 1 kg per square metre
  • Dig in plenty of Searles Premium Organic Compost
  • And leave for a few weeks or longer before planting

If you do this, you’ll be rewarded with a flourishing garden and soil that won’t dry like bricks.

Breaking news

Mulch improves the structure of heavy clay soils.

Clay soils get a bad rap. In winter they are sodden and easily compacted. They take longer to warm up in spring and by summer they’ve turned to concrete. The fine particles stick together so there is poor drainage and lack of aeration leading to poor root growth.

Back-breaking and expensive suggested solutions to improving heavy clay include replacing it all with friable loam or digging in trailer loads of sharp sand and gravel.

But the news is not all bad for gardeners. Heavy clay is often fertile as nutrients aren’t lost by leaching and it retains moisture in dry weather. With a bit of knowhow gardens can flourish on clay without breaking the bank or your back.

Grow potatoes to help break up heavy clay soils.

* Conditioning your soil
* The scientific reasons that gardeners are nicer than other people
* Ground zero

Five ways to garden on clay soil

1. Mulch, mulch, mulch
Adding compost, manure or any sort of mulch from bark shreds to coffee grounds adds humus. Clay particles clump around the humus so aeration and drainage improve. Fork lightly into the top layer of soil or let the worms do the work for you. Keep adding mulch layers as they break down and become incorporated into the soil.

2. Gypsum
Adding gypsum aggregates clay particles too. Don’t add it every year though as it can increase salinity.

3. Rise above it
Plant trees and shrubs on low mounds where they’ll get the drainage they need but still have access to moisture in the clay soil below. Grow veges in raised beds or no-dig gardens avoiding the clay beneath.

4. Avoid compaction
Walking on sodden clay soil or trying to dig it when wet just makes the problem worse. If necessary lay planks over the beds to distribute weight over a greater area. Or use stepping stones so only spots not needed for planting are compacted.

5. Grow clay tolerant plants
Tough herbaceous plants like clivia, hostas, paeonies and daylilies thrive in slightly acidic and nutrient rich clay soils. As a bonus they won’t spread so fast so need dividing less often. Roses, hydrangea, philadlelphus and viburnum will do well too. Many natives don’t mind getting occasional wet feet. Try pittosporum, pseudopanax, flax, oioi and manuka. In the vege patch grow a crop of potatoes which will break up the soil and make it more friable to the advantage of the next vegetables to be planted in that spot.

NZ Gardener

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Improving Clay Soil

If your garden has heavy clay soil, you know what a challenge it can pose to plants, not to mention gardeners. Heavy clay drains slowly, meaning it stays saturated longer after rain or irrigation. Then, when the sun finally comes out and the soil dries, it forms a hard, cracked surface.

On the bright side, clay soils are usually richer in nutrients than sandy soils are. And clay’s tendency to hold water tightly can be an advantage.

Here are some tips for making clay soil more manageable and easier to work.

Tools and Materials

  • Soil test kit or commercial test
  • Organic mulches: compost and aged manure, straw
  • Wheelbarrow or cart
  • Shovel
  • Rake
  • Cover crop (wheat, rye, clover, or oats)

Test soil pH, and adjust as necessary. Clay soils are rich in nutrients, but if the soil is too acidic or too alkaline, those nutrients won’t be available to the plants. Use a home test kit or send a sample to a soil testing lab, then follow the recommendations for adjusting pH. For most garden plants, a pH of 6.3 to 6.8 is ideal. Find a lab near you by checking in your telephone directory, or by calling your local cooperative extension office.

Add organic matter. This helps improve drainage and lighten heavy soil. It also provides nutrients for beneficial soil microorganisms which will, in turn, also help improve the soil. Before planting in spring, add compost and aged manure. A 2- to 3-inch layer worked into the soil to shovel depth is a good amount. Throughout the growing season, mulch with organic materials like grass clippings, shredded leaves, or additional compost. Since soil microorganisms literally “eat” organic matter, make a habit of continually adding it to your soil.

Build raised beds. Because clay soils hold water, creating raised beds can help improve drainage by encouraging water to run off. Raised beds can be a simple mound of soil, or can be constructed out of wood, brick, or stone. To lessen compaction, size the beds so you can reach the middle without stepping in the bed.

Mulch beds over the winter. Driving rain can really pack down bare soil, so keep beds mulched with organic matter both during the growing season and over the winter. A layer of straw over the beds will protect the soil from compaction and reduce erosion; it can also help minimize weed growth. In the spring, transfer the mulch to the garden paths.

Plant a cover crop. A cover crop is like a living mulch. Different cover crops are appropriate for different regions. In the north, winter wheat and winter rye are popular choices; in warmer regions, crimson clover and oats are commonly used. For a winter cover crop, sow after the last crops have been harvested. The following spring, simply till the plants into the soil, adding yet more precious organic matter.


Improving soil takes time, so don’t expect overnight results. On the other hand, if you follow the above steps you should notice some improvement each year. Within a few years, you’ll have rich, plant-friendly soil.

Add compost any time. However, if you are tilling in fresh or uncomposted organic matter, such as a cover crop, leaves, or straw, wait at least a few weeks before planting to allow the material to break down.

LAWN CARE SIMPLIFIED – A Safe and Natural Approach

Clay soils can create problems in lawns. They are dense and compacted and have poor drainage. They stay soggy when wet, and turn rock hard when they dry out in the summer. When soils are this “tight”, necessary air, water and nutrients can not move through them. Roots are stunted and the grass is stressed, weakened, and more prone to disease, insects and even weeds.

Most experienced gardeners know that the best way to improve clay conditions in garden beds is to till or mix in lots of organic matter –such as compost, peat moss, leaves, etc… This process can immediately improve soil aeration and drainage, and will increase the beneficial soil microbes that break down the organic matter and turn it into humus. With humus you end up with an improved and more granulated soil structure. *

But how do you improve clay soil that already has a lawn growing in it? There is no way to till in organic matter down deep into and below the root zone without tilling up the lawn. The standard advice is to ” top dress “the lawn with compost, leave the clippings, fertilize organically and wait… and wait… and wait for all of that organic matter to eventually decompose and improve the soil. But the denser the clay, the longer it will take for this to occur – often many years.

The reason it takes so long for clays to improve when top dressed as above is that the soil microbes necessary for decomposing organic matter are “Aerobic” – meaning they need air/oxygen to survive. Clay, which is made up of microscopic-sized particles tightly bonded together, has a very little air space in it- most of it near the soil surface.

A Faster Solution

If you could increase the amount of air in the clay by just a small amount, you can encourage the beneficial soi-building microbes to generate and grow in numbers. One way to do this is by creating temporary pores and channels in the clay with a soil penentrant called Aerify PLUS –Liquid Soil Aerator and Bioactivator. (Yes, we are promoting our product, but frankly, it is a real difference maker)

Aerify PLUS breaks apart clay bonds to create microscopic air space deep into the clay. Each application can work deeper. It also adds liquid organic matter to help generate and feed beneficial soil microbes of all types (including mycorrhizae) at the same time. It helps improve drainage in your lawn clay, encourages deeper rooting, frees up nutrients and water in the root zone and helps move organic matter deeper into the soil. By improving clay conditions you can create a much healthier lawn in a more bioactive soil.

Additionally, once your lawn clay begins to open up, the soil becomes healthier and earthworms will start to appear in your soil in greater numbers. Earthworms will enhance and speed up the soil improvement process because they aerate the soil as the tunnel up and down. They also digest thatch and other organic matter in the soil and convert it into humus and rich, fertile castings.

If your lawn is growing in a poor clay soil, it will always be prone to the problems that come with clay – compaction, poor drainage, fungus, moss, weeds, poor nutrient availability and color, root-stress and a host of other undesirable conditions. Improve the clay and you will improve the lawn. It is as simple as that.

FYI, I treated my own lawn organically for many years and top dressed with compost as well. Though the top 4-5 inches eventually got pretty good, the clay underneath remained gray and sticky. After a few seasons of treating with Aerify PLUS, it was as if all the organics that I had put in the soil finally became were able to be utilized down deep where I wanted it to go. My lawn clay soil became dark and crumbly more than 1½ feet deep- and earthworms abound.

* Also See Working With Wet Clay Soils in the Garden

Stuart Franklin is President of Nature’s Lawn & Garden, Inc. (, located in the Buffalo, NY area.

He is also the author of Building A Healthy Lawn- A Safe and Natural Approach (Storey Publishing 1988) which is now out of print, but some copies are still available. Write to [email protected]

Copyrighted Materials. No part of this website, its design or any of the content may be used without the expressed permission of the author.

Growing a Beautiful Lawn on a Clay Soil

For some people, having a thick, green lawn is something that just happens. This is few and far between as most people are going to have to do a little bit of work to get the same results. Seriously, we have some customers that their grass just grows, and grows, and grows, all summer long , with minimal weeds. Doesn’t matter if it has been a dry summer with minimal rain or wet and mild. It just grows like a sod farm. If this is you, congratulations, you have officially made me jealous. This is like hitting the jackpot in terms of turf. How does this happen though? Well it all starts with the…

I’ll try and keep this as straight forward as possible when it comes to soil textures as that could be a completely different topic with tons of technical mumbo-jumbo. Soils come in all different shapes and sizes but there are 3 main textures: Sand, Silt, and Clay. There are actually more types but I’ll be using Sand and Clay in my examples as these are on the opposite ends of the spectrum. I should also note that your soil will be a combination of these, it’s pretty rare to have a 100% clay, sand or silt soil.

Clay Soils
Classified as having very small particles, clay soils have a very high CEC (Cation Exchange Capacity). This simply means they have a better capacity to hold nutrients. They also hold water extremely well, suffer from being easily compacted and typically take longer to warm up in spring time. When these are dry they feel like concrete, they are extremely hard and will typically crack.

Sandy Soils
Classified as having the largest particles of any soil type, Sandy soils are sometimes called hungry as they will typically require greater amounts of nutrients and H20 due to leaching and runoff. Leaching simply means they don’t hold nutrients well, when it rains those nutrients are more prone to washing through the soil. Compared to clay, these soils are a dream to actually work with as they are much lighter.

How do you know what type of soil you have? Chances are if you have done ANY digging, you will know if you have clay. A heavy % clay soil is AWEFUL to plant in. Absolutely horrible. If it’s too dry you’ll feel like your trying to break through concrete. If it’s too wet, it will just create a sticky mess, best to wait it out and let it dry a bit. If your still not sure if you have a heavy clay soil, do the ribbon test. Basically, take a moistened bit of soil and rub it between your thumb and pointer. (kinda like your doing a the money gesture) The idea is to create a ribbon. The longer the ribbon, the more clay you have. Anything over 2″ would be considered clayey.

The good news

There is some light at the end of the tunnel. If your willing to put the work in, clay soils can actually be an awesome soil to grow plants and grass in. The biggest benefit to having clay is its capacity to hold an amazing amount of nutrients and water. While you can use many of these tips for your landscape and garden, the rest of this article will be aimed toward the turf.

Organic matter, Mother Earth’s great equalizer

Unless you plan to completely overhaul your soil/yard, you need to start thinking about how you can incorporate more organic matter into your soil. Organic matter can be compost, lawn clippings, leaves, or even organic fertilizer. Simply put, its almost anything carbon based the will biotically deteriorate/degrade over time. Biotically meaning the soil organisms will break it down. Maybe not so simple I guess. Basically they will amend your soil over time and act as a medium to increase your drainage while keeping its water and nutrient hold capacity.

Amending an EXISTING lawn
Here are a few things you can do for your existing turf to increase its organic matter:

Leave your grass clippings
I recommend that EVERYONE does this, no matter what kind of soil you have

Mulch your leaves
Instead of bagging you leaves, mulch em’. Every week during the fall season, mow the lawn and mulch those leaves. Sometimes you may need to mow a couple times throughout the week if theres some heavy tree cover. Please note there are times when there’s just too many leaves and you will HAVE to bag them as to not suffocate your lawn.

Use an Organic Fertilizer
I am certainly not a 100% organic or go home kind of guy, but they definitely can help with a heavy soil. They will promote activity of those soil organisms and increase the amount of organic matter in your soil just like leaves or grass clippings. Remember, an Organic Fertilizer could be anything from Bone Meal to Milorganite. (This is what we use) It should also be noted that an Organic Fertilizer will be lower in actual nutrients and slower releasing meaning you’ll likely have to put in on multiple times throughout the growing season.

Topdress your lawn with a nice compost/topsoil mix
A VERY good way to start amending your soil is to add a very thin layer (around ¼”) of compost or 50/50 mix on top of your lawn. There are actual machines that can do this, but if your lawn is smaller, grab a wheelbarrow and start spreading! Around here we have a supplier that has a very very nice 50% topsoil, 50% compost mix that works great.

Aerate your lawn
I love aeration. The idea behind amending the soil is to get those amendments deeper into rootzone of the soil over time. Just doing the things I listed above will absolutely help, but adding aeration will drastically increase the depth and time it takes for those amendments to get into the rootzone. It will also help relieve compaction that clay has such a hard time with. Aeration does a lot for your lawn, read more about it HERE.

Putting it all together

Here is what I would recommend doing for someone willing to put in some work to amend their existing turf. It does take a long time to completely amend your soil. This is not a one time thing but a complete change of routine for your lawn. Doing this year after year will help your clay soil drastically and give you a much stronger and healthier lawn.

  1. Start using an organic fertilizer throughout the season. We use Milorganite and apply it 5 times throughout the year.
  2. During the summer, start mowing tall (it will help with keeping your soil cooler along with many other benefits) and keep the lawn clippings on the lawn.
  3. Make sure you water your lawn and keep it from drying out. A bone dry clay soil is going to be rock hard and not allow water/nutrients to get into the rootzone
  4. When the temperature start to get cooler but before the leaves start dropping, start by aerating your lawn, followed by an over-seeding of appropriate seed type and apply an organic fertilizer. Afterwords spread a thin layer (¼”) of compost or 50/50 mix on top of your lawn.
  5. During the fall start mulching your leaves. Remember, you may need to bag some of your leaves to prevent your lawn from becoming suffocated. If your new seed is starting to pop up, be extra careful not to damage it.

Remember, this is something you need to be doing EVERY year. You simply CANNOT expect to do this one year and have an outstanding lawn the next. Yes, you will start to see improvements during that first year but that’s not what we are after. What we are after is a long term change in the actual soil and that takes time. Follow these steps and after a couple years your WILL have a much healthier, thicker, greener lawn.

One thing I should probably go through is what you should absolutely not be doing:

    • Add sand to clay
      But wait, wouldn’t adding the opposite of clay create an awesome soil? No, It won’t. You will however create a VERY nice concrete like soil. Seriously, don’t do it.
    • Smother your lawn with leaves
      Mulching them is great. Mulching too many at once is not. If you have a thick layer of Bur Oak leaves that’s 6″ deep. Don’t even try to mulch them. Instead you should be mulching it more often as to not allow for them to pile up. Or bag some of them. Trees such as the Silver Maple typically have leaves that can, quite literally, be turned into dust. Even large amounts are great for mulching.
    • Add wood chips to the lawn
      Not sure why anyone would actually try this, but don’t. Wood chips actually pull nitrogen out of the surrounding soil when they decompose. Ever notice that grass grown on top of an old tree that was chipped out will start nice and green but quickly fade to lime green? It’s the wood chips underneath that grass.
    • Allow your clay soil to dry out
      Once they become dry they will be extremely hard. This means water and nutrients will literally not percolate down into the soil. Keep them moist throughout the heat and you won’t have any issues.
  • Mow your lawn short
    The higher you cut your grass, the more shade it will provide to the soil. That means it will stay cooler and require less water. Remember dry soil= rock hard soil.

Soil and Site Preparation for Lawns

Properly preparing the soil is critical to the success of home lawns.

Success or failure of a home lawn is closely tied into how well the soil and site was prepared prior to lawn establishment.

Eliminating weed problems existing on the site is an important first step. Perennial weeds, such as quackgrass or tall fescue, need to be controlled prior to lawn seeding or sodding. Weed control options include digging by hand, repeated soil tillage or using a systemic (moves within plant) nonselective herbicide, such as glyphosate, sold as Roundup and other trade names. Organic products are becoming more popular as well. Read, understand, and follow all label directions whenever using any type of control product to be sure you will be getting the expected level of control necessary.

Before seeding or sodding, it’s important to thoroughly work the soil. Amend poor soils, such as heavy clay, by adding organic matter. Sources include compost, rotted manure, peat, and quality topsoil. Sand is not suggested as a material to improve clay soils for home lawns.

In addition to modifying the soil structure organic matter contains micro organisms that work together with the roots of plants to absorb the nutrients in the soil, so there are additional benefits of using organic matter as part of the soil building program. Incorporate these materials into the existing soil, rather than layering them on the surface. A goal is to have six inches or more of well prepared soil, and beyond that is impractical around large trees where many roots are found within the dripline.

Soil testing is suggested prior to establishment and should be done during the planning process. Soil testing reveals the oil pH and amount of available nutrients such as phosphorus (P) and potassium (K). If major modifications are needed, it is easier to make these prior to establishing the lawn. Check with your local Cooperative Extension Office for details on how to take a soil test and go to ( for a listing of soil test laboratories that provide homeowner recommendations.

Starter fertilizers should be mixed into the soil surface prior to lawn establishment. These are typically high in phosphorous. Balanced fertilizers typically have balanced ratios of nitrogen, phosphorus, and potassium (N, P, K), such as 10-10-10 or 12-12-12. Balanced fertilizers can be used if a starter fertilizer is not available. Soil test results may show a shortage of phosphorus or potassium, which would influence the decision of the fertilizer formulation used.

When preparing the soil, it’s important to establish a favorable final grade. Rough grading should include removal of any rock or other debris. Avoid burying construction debris, as this could cause problems for the grass later. Eliminate any depressions or raised areas. Final slopes should be one to two percent away from buildings (1 to 2 feet drop per 100 feet of run) to assure good surface drainage.

Soil preparation should be done when the soil is not too dry or wet as tillage will destroy soil structure, and create problems with air and water holding capacity and drainage after a rain event. It can take years to return to its former state.

Taking shortcuts in soil and site preparation often leads to assorted lawn problems later. Take the time and effort to do a thorough job before seeding or sodding that includes soil testing, nutrient and soil amendments, creating uniformity of the subsoil and final grading.

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There’s no break for people who garden in clay

CORVALLIS – When you walk about your yard on a wet day, do your shoes stick in the mud? Could you make ceramic pots out of the soil in your garden? Odds are you have clay soil, one of the biggest challenges to the home gardener.

Finely textured clay soils are difficult to work up and develop into a good seedbed. If the clay is dry, it tends to be very hard and lumpy. If it is wet, it tends to be very sticky and difficult to manipulate. It seems like a gardener’s nightmare.

But clay soils have their attributes, says Linda Brewer, teaching assistant in the Department of Soil Science at Oregon State University.

“Clay soils hold huge amounts of plant nutrients because they have elevated cation exchange capacities,” said Brewer. This means they are able to hold on to nutrients, fertilizer and pesticides.

Another plus for clay soils is that they hang onto water really well.

“Clay soils hold huge amounts of water at very high tensions because the spaces between the clay particles are so fine,” explained Brewer. “The largest clay particle is more than 1,000 times smaller than the smallest sand particle.”

The best way to improve clay soils is to mix organic materials thoroughly with existing soil, explained Brewer.

Bark, sawdust, manure, leaf mold, compost and peat moss are among the organic amendments commonly used to improve clay soil. Two or three inches of organic materials should be spread and rototilled, forked or dug into the top six or seven inches of your garden beds.

“Clay soils are highly structured at the atomic level, much as crystals are,” said Brewer. “No amount of sand can be added to a clay soil to change its texture. The large sand particles tend to provide a surface onto which the tiny clay particles adhere. The result can be a more difficult soil to manage than the original clay.”

When a large amount of organic material is added to the soil, microorganisms multiply rapidly. Since they construct their bodies from the same nutrients that plants use, soil nutrients can be relatively unavailable for a time after an addition of manure or compost. This condition may persist until the organic material is broken down and nutrients are released.

To overcome the temporary lack of nutrients, gardeners might try adding low nitrogen organic material to the soil in the autumn, or smaller amounts at a time in the spring, when warm weather will hasten break down. Or sprinkle in some fertilizer, such as ammonium sulfate at the time of tilling to give an immediate source of nutrients.

Organic matter in soil serves as food for earthworms, insects, bacteria and fungi-they transform it to soil nutrients and humus. Through this decomposition process, materials are made available as foods to growing plants. In finely textured clay soils, organic material creates aggregates of the soil particles, improving drainage and making it easier to work. Earthworms are especially helpful in making and keeping soil porous and well draining, said Brewer.

Fertile soil with good tilth does not come about with a single or even several additions of organic material, but from a consistent soil-building program. “Repeated additions of organic matter do change the physical properties of clay soils on a broader level, but these additions must be regular in order to maintain the changes,” said Brewer.

“There’s no break for people who garden in clay,” she said with a laugh.

When I was growing up my Mom always complained to my Dad about her garden and flower beds. She would say things like “Nothing grows in this red dirt!”, or “I’m not planting anything this year, it never grows!”

I always thought Mom just didn’t have a green thumb.

Fast forward about twenty years, and now I understand her struggle.

Digging in my flower beds and garden used to be like playing in a big mud pie that was left out in the sun to dry. The flowers and vegetable plants I planted always showed signs of being over-watered. Because yes, I have clay soil.

I’ve figured out a few ways that have improved the quality of my garden and flower bed soil. These tips have made my efforts in the garden more fruitful and less back-breaking.

Let’s start with the first step: determining if you actually have clay soil. Then I’ll show you what to do to to fix it.

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Discovering The Signs Of Clay Soil

Dry clay cracks in the heat, creating crevices that weed seeds can fall into. Source: Kitty Terwolbeck

For me, the largest problem with my heavy clay soil was the compacting of the dirt. It was heavy and wasn’t easy to till or dig into.

In addition to that, I also have waterlogged soil every spring after the snow melts. Compaction leads to poor drainage, and that leads to clumps in my tiller. Plants have a hard time developing good roots, as well.

First, you need to determine if clay is the problem. This simple test will help you determine the type of soil you are dealing with.

Pick up a handful of soil. Squeeze it in the palm of your hand. If it forms a sausage shape and stays together when you open your hand its clay based soil. Sandier soils will crumble more readily if you poke at the soil blob.

Also, check out your soil’s color. Many are rich in iron oxide, which gives soil a reddish or rusty tone. This is not universally true, but may offer a helpful hint. Red clay soils tend to be fairly common around the world.

Finally, there’s the “clay snake” method. Make that sausage shape mentioned above, then roll it between your fingertips to make it into a thin, long snake. Soil that stubbornly clings to its snake shape over 2 inches of length is likely clay.

How To Amend Clay Soil

Adding mulch to your heavy clay soil builds the soil over time. Source: charel.irrthum

Here’s some tips that I’ve discovered that helped improve my clay soil. These also make my gardening more enjoyable and less backbreaking.

Check The Soil Moisture First

There’s two ways of working with clay soil: when it’s really wet, or when it’s really dry.

Anything in between will cause the soil to stick to your shovel and become agonizing to deal with. It clumps and clings, and is just impossible. So it’s important to only dig when the soil is either very muddy and extremely soft, or when it’s fully dried out.

Even then, be careful. If you’re working with the soil while it’s wet, you’re going to create hard clods of dirt once it dries out. The only way to avoid this is to amend the soil heavily while it’s still muddy, so you can break up all the clods and evenly blend the amendment in.

Don’t Overwork The Soil

Related to the last section is to avoid overworking your soil. If you go out and turn your wet soil without amendment, all you’ll end up with is a bunch of heavy, dry clods. Anyone who’s ever dealt with heavy clay blobs knows that they’re hard to break apart later!

Along the same line, try to avoid over-compacting your soil as well. Don’t walk on areas you’re improving. Clay compacts itself naturally if you, the kids, or your pets walk on it. All you’re doing is making the problem worse.

Add Quality Amendments

No matter what time of year it is, adding aged compost can be beneficial. Compost is filled with plant matter that will help break up the clay particulate. It’s also just really good for your plants in general, and can help improve their growth significantly.

Biochar is another option. This light and porous charcoal can help improve drainage in clay soil while it also adds more organic matter to break up clods. It’s gained popularity in farming, too, and is starting to replace gypsum in a lot of areas.

Consider opting for perlite if you’re still having drainage issues. Perlite helps hold open pathways for water to filter through, and also keeps your soil aerated, which is good for breaking down plant matter like compost.

Looking for how to improve clay soil for lawns? Consider using greensand. Greensand is made of a mineral called glauconite, and it improves clay soil while adding some great micronutrients and a good potassium kick for your grass. It works well in gardens, too!

When all else fails, consider working in a commercial soil conditioner blend. There’s many options available on the market, and working that in over time will gradually improve the upper structure of your soil.

Consider Soil Builder Mulches

Amending the soil with straw mulch improves it as it breaks down. Source: Joe Hoover

Cover your worked areas with compost, bark, mulch, grass clippings, fall leaves, or even manure. I used shavings from my barn. Try to coat the worked areas 2-3″ deep with these organic matter.

When you add products like this over your soil, the materials begin to decompose and break down. Over time, they will work themselves into your soil, helping to keep the soil broken up and workable in subsequent years.

Plant A Cover Crop

When you’ve plucked the last head of cabbage in the fall, plant a cover crop. I like using timothy hay and then working that into the soil as an organic compost in the spring. I’ve also tried other cover crops like clover, alfalfa, and buckwheat.

Even with these tips, it isn’t going to be a quick turn around. Sorry, but it may take several years before you notice a difference in your garden soil.

Should I Use Gypsum?

Often, the immediate recommendation of garden centers is to add gypsum to your soil. Don’t jump straight to doing that, though. Make sure it’s right for your garden.

The effects of gypsum in soil to break apart the clay granules are short-term. In fact, it often only lasts for a few months time. And it has other effects that are much more long-term and problematic.

Adding gypsum to your soil can cause leaching of mineral and nutrient levels. Leaching of aluminum or sodium can be good as it detoxifies the soil, but leaching of iron or manganese can cause nutrient deficiencies in your plants. It may also cause other mineral deficiencies.

In addition, gypsum may make it difficult for beneficial mycorrhizae in your soil to do their jobs. Those beneficial growths often help your plants take up nutrition more easily, and you don’t want to slow the growth of your plants!

A Washington State University study thoroughly examined this topic. The consensus was that while there are applications for commercial farmland, or for extremely hard-compacted soils or sodium-polluted soils, it just isn’t very effective in most home gardens.

Stuck With Clay? How to Garden Anyways

Try to break up the hard-packed clay clods before planting, and add compost. Source: kahunapulej

So if you have clay soil, how do you get around it? Well, let’s break that down a bit further.

Rise Up

Build raised beds on top of a smaller area. I used top of the line soil and grew my tomatoes in raised beds.

This made it easier for me to work in the garden, as the beds put the plants at a much more workable height. It also kept the dogs and kids from compacting the soil that I was working so hard to change.

There’s many different types of raised beds, from planter-style ones to much more elaborate garden styles. You’ll make your garden look better and be able to grow even without doing the necessary soil amendments on your clay.

Warm And Protect Your Soil

In the spring the soil tends to become waterlogged due to the amount of snow we receive. This makes starting vegetable plants in the garden difficult.

My solution was adding window greenhouse boxes made from recycled window panes. This type of small greenhouse or cold frame can easily be built in few hours or less.

A cold frame or greenhouse-type structure will keep the snow off of your growing area, which helps reduce drainage issues in the garden bed. It also keeps the soil beneath it warmer, which helps with plant germination and growth.

Layer On The Mulch

I always mulch my beds over the winter, because snow and rain can really pack down bare soil. Wood chips work extremely well. You can even layer gardens with a thick layer of straw or grass clippings.

Mulch also helps prevent your soil from baking into an extremely hard state during the summer months. If you have areas that look like concrete once the sun has baked them for a while, mulch can help keep them soil-like instead of turning them into impenetrable slabs.

Not only will your mulch slowly work its way into the soil beneath and improve its tilth, but as it breaks down it will provide added nutrients for your plants. It has the added perk of helping prevent many kinds of weeds!

Plant Suggestions When Growing in Clay

Corn growing in a garden that has heavy clay. Source: laura.bell

Plants that grow in this soil type span a wide category. Here’s a few different options for you to choose from.


Your grass types depend on your location. Different grasses work best in different climates.

For people in cool regions, varieties of cool season grass that grow in a clay-loam soil include fescues (especially hard fescue and red fescue), annual and perennial ryegrass, colonial bent grass, and Kentucky bluegrass.

People in warmer regions may want to plant plugs of warm-season grasses such as Bermuda grass, buffalo grass, Saint Augustine, or zoysia. All of these tend to tolerate clay-loam soils.


In the years of amending the soil I have found some plants that thrive in clay. I think this information can save you a lot of time and effort, spare you from destroying plants, and save some money, too!

Some vegetable crops that grow well include lettuce, chard, snap beans, broccoli, Brussels sprouts and cabbage. Rice also grows well in clay due to the constant moisture and heaviness of the soil.

Other shallow-rooted brassicas such as cauliflower or broccoli can also thrive in clay, as can sweet corn, squash, or pumpkins. The latter three have strong roots that can shove the clay aside.

Mulching around your vegetables can reduce the risk of fungal diseases from soil moisture or mud splashing onto plant leaves.

If you don’t want to build raised beds to plant other crops in, you can always trade with neighbors or friends for plants that grow better in amended soils, and simply stick with those which work with your soil type.


If you have flower beds or are growing a flower garden, these are some of the best performing plants in my beds.

  • Asters: Daisy-like flowers in pink or purple hues.
  • Black Eyed Susans: Rich gold petals with a dark brown or black center.
  • Russian Sage: This can be invasive, but also very beautiful with small purple flowers.
  • Daylilies: A wide variety of colors available. These flowers open in the daylight and close up during the evening.
  • Yarrow: This yellow flower is perfect for dry flower arrangements.
  • Coreopsis: These are great for borders, and usually have pink or purple flowers.
  • Coneflowers: Purple-petaled perennials that are great additions to any garden.

If you want other plants that won’t thrive in clay, buy containers and place them throughout your yard. Not only does it give you the ability to grow plants that prefer lighter soils, but containers provide variable heights and look amazing when they’re in full bloom.

In my experience bulbs do not do well. Not only do they need warm soil, but they don’t do well when soil is soggy and can develop bulb rots.

Best Cover Crops

Some of the best cover crops for clay soil are clover, winter wheat and buckwheat. Crops like alfalfa and fava beans have a deep tap root so they tend to pull nutrients into the topsoil and at the same time help with compaction.

If you do opt to do a cover crop, till it into the soil at the end of its growing season. This adds extra plant matter that breaks down in the soil, adding more nutrition while breaking up soil clods. Be sure to till at least a couple weeks before replanting to start the decomposition process.

Clay Soil Benefits

Once graded, clay can be an excellent surface for a road during dry weather. Source: BluesDawg

Surprise! It’s not all bad news.


Many clay soils are naturally more fertile than other soil types. The natural compaction of the soil tends to slow leaching, which would otherwise wash away many plant nutrients.


You don’t have to water as often in clay. It retains moisture more readily than other types of soil, and you don’t have to add vermiculite or other water-retention amendments.


You may not need to fertilize as often. Because the clay particles are so fine and tend to cling together, fertilizer tends to stay in the soil for longer. However, this doesn’t mean you don’t need to fertilize at all! You just may have to do it less often.

Long Term Root Development

Once plant roots have become established, the dense structure of the soil can be a great foundation for many types of plants. The roots will remain securely in place, and may be partially protected from temperature changes.

I’ll bet right now you are feeling a bit better about that garden soil you’ve been cursing!

Don’t Skip This Important Step

No matter how you opt to improve your soil, don’t miss one year of amending your soil once you start. Keep at it to build better quality soil.

It doesn’t take long for the soil to return to its original hard, clumpy state if you don’t keep adding new material to it. Since you went through a lot of effort to amend the soil the first time, maintaining it year after year is easier than starting from scratch!

After many years, you may be able to change the quality of your soil overall, making this less of an annual necessity. But it’s better to go into it knowing that you need to do this simple chore every year for a while. It’s worth the time and effort.

About The Author: Alex writes for Woodtex, a preferred nationwide builder of prefabricated storage sheds, garages, and cabins. He is passionate about sustainability, healthy living, good food and exercise.

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Improving soil structure

Most gardens have soil that provides something less than the ideal environment for many garden plants. Perhaps it’s rocky or scraped bare from new construction; perhaps it’s too claylike or too sandy to suit the plants you want to grow. While changing a soil’s basic texture is very difficult, you can improve its structure–making clay more porous, sand more water retentive–by adding amendments.

The best amendment for soil of any texture is organic matter, the decaying remains of plants and animals. As it decomposes, organic matter releases nutrients that are absorbed by soil-dwelling microorganisms and bacteria. The combination of these creatures’ waste products and their remains, called humus, binds with soil particles. In clay, it forces the tightly packed particles apart; drainage is improved, and the soil is easier for plant roots to penetrate. In sand, it lodges in the large pore spaces and acts as a sponge, slowing drainage so the soil stays moist longer.

Among available organic amendments are compost, well-rotted manure, and soil conditioners (composed of several ingredients); these and others are sold in bags at many full-service nurseries, or in bulk (by the cubic yard) at supply centers. Byproducts of local industries, such as rice hulls, cocoa bean hulls, or mushroom compost, may also be available.

Finely ground tree trimmings (wood chips) and sawdust are also used, but because they are “fresh” (“green”) amendments, they’ll use nitrogen as they decompose, taking it from the soil. To make sure your plants aren’t deprived of the nitrogen they need, add a fast-acting nitrogen source such as ammonium sulfate along with the amendment (use about 1 pound for each 1-inch layer of wood chips or sawdust spread over 100 square feet of ground).

Though the particular organic amendment you use is often decided simply by what’s available at the best price, many experts favor compost over all other choices. Vegetable gardeners in particular prefer compost, and they often also add plenty of well-rotted manure to their planting beds.

Adding amendments: when and how

New beds for landscape plants should be amended before any plants go into the ground. For long-term benefits, choose an amendment that breaks down slowly. Shredded bark and peat moss hold their structure the longest, taking several years to decompose. It’s a good idea to include compost in the mix as well; though it breaks down in just a few months, it bolsters the initial nutrient supply available to soil microorganisms–and these will contribute humus to the soil, improve soil aeration, and help protect your new plants from some diseases.

In beds earmarked for vegetables and annual flowers, amend the soil before each new crop is planted. Compost and well-rotted manure are preferred by most gardeners, since they dramatically improve the soil’s structure, making it hospitable to the fine, tiny roots of seedlings. Unamended soil may dry into hard clods that small roots cannot penetrate, and plants may grow slowly, be stunted, or die as a result. Manure and compost break down rapidly–manure in a few weeks, compost in several months–so be sure to replenish these amendments before you plant each crop.

To add amendments to unplanted beds like those just discussed, spread the material evenly over the soil, then work it in by hand or with a rototiller to a depth of about 9 inches. If your soil is mostly clay or sand, spread 4 to 5 inches of amendment over it; once this is worked in, the top 9 inches of soil will be about half original soil, half amendment. If the soil is loamy or has been regularly amended each season, add just a 2- to 3-inch layer of amendment; you’ll have a top 9-inch layer of about three-quarters original soil, one-quarter amendment.

Permanent or semipermanent plantings of trees, shrubs, or perennials benefit from soil amendment too, but you need to do the job without damaging plant roots. It’s often sufficient simply to spread the amendment over the soil surface as a mulch; earthworms, microorganisms, rain, and irrigation water will all carry it downward over time, gradually improving the soil’s top layer. If the plant isn’t a shallow-rooted type (that is, if it doesn’t have many roots concentrated near soil level), you can speed up the improvement process by working the amendment into the top inch or so of soil, using a three-pronged cultivator.

Where the climate is generally mild and winters are rainy, amend the soil in established plantings annually after fall cleanup. In cold-winter regions with spring and summer rainfall, do the job as you begin spring gardening.

Sand and peat moss: good amendments for clay soil?

Sand is often recommended to lighten clay soil. This seems a practical suggestion: after all, clay is the finest-textured soil and sand the coarsest, so mixing the two should result in just the right blend. It’s not that simple, though. The problem is that you must add a great deal of sand to make a difference–at least 4 inches of coarse sand to the top 6 inches of clay soil. Improving even a moderate-size planting bed thus requires a great deal of heavy sand and heavy labor. Many gardeners compromise by simply sprinkling a little sand on top of their clay soil, but such small amounts do no good; in fact, they actually compact the soil further.

Peat moss has long been a favorite soil amendment because it breaks down in the soil more slowly than manure or compost and can thus be replaced less frequently. It is also highly absorbent; it holds water in the soil longer than many other amendments do, making it especially beneficial in sandy soils. But if your soil is naturally claylike and drains slowly, the super-absorbency of peat moss can exacerbate the drainage problem, especially if you have heavy winter rains.

Shaping Clay Into Perfect Garden Soil

There will be times while working in your yard or garden when you might feel a little like Goldilocks.

If your soil is hard and dense, the water and nutrients your plants need will be unable to reach their roots. If your soil is loose and crumbly, water will drain from the soil before your plants can absorb it.

Your goal is to get your soil just right so that your lawn or garden can thrive.

Because clay soil is so dense, some gardeners, farmers, and lawn care professionals consider it the most challenging type of soil.

However, working with clay soil isn’t an impossible task. All you need are the right kinds of material to add to it and a garden tiller to blend it all together to get healthy, bountiful soil.

What Is Clay Soil?

All soil is a mixture of four components:

  • Minerals (broken-down rock, such as quartz)
  • Organic matter (such as decaying leaves)
  • Air
  • Water

You might be surprised to learn that the ideal soil for growing crops contains only five percent organic matter! Air and water take up a full 50 percent of the soil space, and minerals make up the remaining 45 percent.

That mineral portion is what determines whether you have clay soil. When it comes to soil, minerals are divided into three categories:

  • Sand: 2 mm – 0.05 mm particles
  • Silt: 0.002 mm – 0.05 mm particles
  • Clay:

Don’t worry. You don’t need to take out a ruler and try to measure tiny bits of rock in your lawn or garden bed.

The important point to know is that clay soil contains a lot of small, fine particles. They pack tightly and make it difficult for water and nutrients to move where they need to go. They also can block the growth of your plants’ roots.

How Can I Tell If My Soil Is Heavy in Clay?

There’s an easy test that gardeners have used for a long time, no microscopic rulers required:

  1. Roll some of your soil into a small ball that fits in the center of your palm
  2. Squeeze the ball until it’s firm
  3. Hold the ball between your thumb and index finger
  4. Begin to push upward with your thumb so that a ribbon of soil forms at the top
  5. If the soil can form a smooth, unbroken ribbon two inches or longer, it contains a high amount of clay

In most situations, a picture is worth a thousand words. Testing your soil’s texture is no exception:

Image credit: “Soil texture,” Lynn Ketchum/Oregon State University. Made available through a Creative Commons 2.0 License.

The feel of your soil will help you figure out if it’s heavy in clay, too. Wet clay soil tends to feel sticky, while dry clay soil tends to feel hard and almost brick-like. It’s easy to imagine just from your sense of touch how those small mineral particles can cause big problems in a yard or garden.

How Do I Amend My Clay Soil?

You can’t simply purge all the clay particles from your soil, and you wouldn’t want to, either. Having some clay in your soil will prevent water and nutrients from leaching away before your plants can use them.

However, you can improve the balance of your soil’s solid components, also called its structure. The best way to do that is by mixing in other materials, which, when added to soil, become known as amendments.

You have several possible amendments you can use to improve clay soil:

  • Organic matter is your best bet, and the easiest, most affordable form of organic matter you’ll find is compost. A layer of compost spread about three inches thick over your garden plot will be enough to break up your soil (and provide plenty of nutrients, too).
  • Some people think that sand helps break up clay because of its loose, grainy structure. However, clay particles tend to stick to sand particles and form unmanageable clumps. You need to add a lot of sand (about three parts coarse sand to one part clay soil) for the sand to be an effective amendment.
  • Minerals like lime and gypsum can loosen clay soil, but lime also can change your soil’s acidity, and that affects which plants will successfully grow. Lime additionally risks thickening your soil by reducing its moisture-retaining capacity too much. Only use lime after testing your soil’s pH level and consulting with a soil expert.

No matter which amendment you choose, you’ll need to mix it into your soil. This is where your garden tiller becomes essential.

To get the most out of your soil amendment, till it into your soil as deeply as you can. Although most cultivators can dig deep enough, you might find a garden tiller more efficient if your clay soil is especially dense. Tilling to a depth of six to eight inches will encourage healthy growth in your plants’ roots.

The best time to till is the beginning of the growing season before you’ve sown your seeds. Avoid tilling when your soil is wet—it will be heavier and more difficult to till and will likely become compacted. Soil that’s slightly moist is ideal for tilling.

What If I Don’t Have Enough Clay?

The opposite of clay soil is sandy soil. It’s lighter in color than clay soil, will be difficult to roll into a ball, and won’t form a ribbon.

Sandy soil presents a completely different problem than clay soil. Because its particles are so big and have such large spaces between them, it doesn’t hold on to water or nutrients long enough for plants to absorb them.

Although the problem is different, the solution is the same. Adding several inches’ worth of organic matter such as compost and tilling it in as deeply as possible will form manageable clumps in your soil and leave a healthy amount of space between them.

How Should Healthy Soil Look?

The ribbon test is just as helpful after you’ve added your amendments.

Form your ball of soil and push it upwards with your thumb to create a ribbon, just as you did earlier. If your ribbon breaks when it gets to be about an inch long, your soil has a good consistency.

You can further check your soil by wetting a pinch of it and rubbing it between your thumb and forefinger. Healthy soil should feel neither gritty nor silky smooth, but in between those two textures.

These simple tests will let you know that your soil is just right. When you use your tiller to mix amendments into your difficult lawn or garden soil, you’ll find that you can build soil where you can grow your plants happily ever after.

NEXT: How to Pick the Perfect Garden Tiller

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PHOTO: Sam/Flickr by Leslie J. Wyatt May 29, 2015

It’s no secret that garden soils come in many variations—silty, loamy, sand or clay—each with its own characteristics and challenges. Perhaps the most challenging to amend is clay soil, but all is not lost. You just need to work a different amendment angle.

First off, let me say that clay soil is not all bad. It may be difficult to work with and in need of some TLC, but it has some good things going for it. Many clay soils, for example, are rich in minerals. Plus the cation exchange capacity—aka, the soil’s ability to hold onto water and nutrients—is quite high, which is especially useful in drier parts of the country. Clay soil is made of tiny particles a mere 0.002 mm in size, causing it to drain slower and retain water better, meaning you can water and fertilize less often. The density also gives plants something firm to sink their roots into, enabling them to withstand temperature and moisture extremes. Also, plants overwintered in clay soil are less likely to heave out of the ground. So all in all, clay can be downright friendly.

Of course, there are some cons, and these are what we usually hear about. That denser quality that helps plants stay planted makes clay soil heavier, thus harder to till or dig, and if it’s too dense, it can even smother roots. Clay is also more likely to compact, as anyone who has encountered clay after rain can affirm as they scrape the gunk off their shoes and garden tools. In fact, digging or tilling in clay soil that is too wet actually compacts rather than aerates the soil. Not so good. And with that high CEC, clay can hold both good and bad minerals, salt being one of the primary offenders, which can take some time to properly amend. Finally, clay soil in boggy areas can keep plant roots from receiving the oxygen they need.

So what’s a gardener with clay soil to do?

Your main goal should be improving the aeration and drainage of your clay soil using a variety of soil amendments. “Adding organic soil amendments to the soil lightens soil texture, discourages compaction, adds nutrients, improves drainage and aeration, moderates soil temperature, and provides pore space, which is essential to plant growth,” according to the Cooperative Extension at North Carolina State-Durham. “Clay without organic matter is like a flattened deck of playing cards. Adding organic material jumbles the cards, permitting water and oxygen to enter the soil.”

You can amend the soil by working fibrous materials into it with a long-term goal of incorporating sufficient amounts of fiber into the soil to bring your humus level between 4 and 5 percent. Mulching can be part of this picture. While mulch doesn’t penetrate too far into the soil unless you till or work it under, it does keep water from running off easily, preventing moisture loss. Plus, it slowly adds compost as it breaks down, keeps your soil cooler, and also helps keep your shoes clean!

Here are a few great mulch options for clay soil to get you started on the way to a manageable garden bed.

1. Wood Chips

Wood chips are readily available at many commercial stores, and some areas even allow gardeners access to their piles of chipped branches resulting from around-town cleanup. Because wood chips have high carbon content, they need nitrogen during the decomposition process. Small wood particles, such as sawdust, will actually leach nitrogen from the soil to help with decomposition, which could ultimately hurt your nitrogen-loving plants. However, you don’t need to work about this as much with larger particles, like wood chips. When used as a mulch instead of being tilled into the soil, nitrogen tie-up is minimal. Wood chips are best left to the moisture and earthworms to slowly break down, enriching the soil over time, and being replenished as needed.

If you’re mulching around trees or shrubs, avoid contact with the trunk or stem, as this can provide habitat to slugs, sow bugs and mice that could damage the tree. Also keep in mind that wood chips weather with age: While they might start out a nice, rich color, they eventually end up graying. Cornell University says that just adding more mulch to “freshen the look” not only wastes mulch but can suffocate the roots of shallow-rooted species and cause cankers to develop around the bases of susceptible trees and shrubs. Instead, renew the mulch every two to three years, working the old chips into the soil before adding a new layer.

2. Tree Bark

Commercially available bark mulches are predominately by-products of fir, redwood, pine and spruce logs, and are sold shredded or as chunks or granules. Granules are more suited to working into the soil, while chunks and shredded bark work better for mulching.Not only is tree bark easy to obtain, it tends to hold its color better than wood chips and resists wind dispersion and compaction.As with wood chips, keep bark away from trunks and stems to discourage damage to the plant.Some barks, can be toxic to young plants. If you notice a sour smell, exposing the mulch to air can help leach the toxins out so the mulch is usable. Bagged bark has generally been weathered long enough that this is not a concern.

3. Hulls/Shells

A number of mulches on the market are made from the hulls or shells of various plants. Here’s a brief overview of some to consider:

  • Nut shells from pecans, hazelnuts, and others make long-lasting mulches that hold their rich color well and add texture to the landscape. These are available commercially, especially in regions where the nuts are grown.
  • Buckwheat hulls are long-lived with a neutral coloring that complements plantings. They are, however, finely textured, and can blow around in windy spots. Hot, humid weather may bring out a slight odor some people dislike.
  • Cocoa bean hulls are another great choice for mulching: They have a rich, chocolate color and a pleasing odor, and these roasted hulls look great around plantings. Cocoa bean mulch does tend to pack down over time, so stir it occasionally to ensure that roots get enough air.Also be aware that they are toxic to dogs, so this wouldn’t be a good choice if any neighborhood dogs have access to them.

How to Loosen Clay Soil with Bark Mulch

If you have clay soil you need to loosen it to have any success at all with gardening. Bark mulch is a good way to do this. If you are working on a large area, it is recommended that you use a garden tiller as digging clay soil can be a back breaking job. You can rent one at your local home and garden store for a small fee.

Prepare Your Soil

Clay soil is very heavy and dense. Watering and digging most times will only result in it compacting again and killing the roots on any plants or grass you try to grow. Before adding anything to the soil it needs to be loosened. Using either a tiller or doing it by hand, you will need to dig to a depth of at least 8 inches and turn the soil over of the entire area you are working. Once it is dug up, use a hoe to break up any dirt clods until the area is relatively smooth. Clay soil will seem heavy and wet even if it hasn’t been rained upon for sometime.

Adding Mulch

Once the soil is turned over, you will need to start adding your amendments. If you are adding only mulch you should add at least a depth of 6 inches of mulch and turn the soil over again to mix it well. You can then add any plants, shrubs or flowers you want to plant. It is also a good idea to add mulch to the top of the flower bed or planting area to a depth of at least 4 inches. Each year, work this top mulch into the soil to further amend it, and then put another 4 inch layer on top. It can take several years to get a truly good planting area with rich, dark soil; this won’t be a one time job.

Adding Other Amendments

If you wish to assist the mulch in its job and not have to amend the soil as often, you can also add about 3 inches of peat moss, 2 inches of manure and an inch of sand with the mulch. Broadcast lime over the entire area in Spring and again in Fall to further loosen the soil.

You should also consider having a compost heap to create rich dark compost to add to your mulch to loosen the soil more. Compost is free since you create it yourself with grass clippings, vegetable waste and other things you would normally discard. It is also earth friendly and helps you avoid having to use chemical fertilizers.

Clay soil can take several seasons to loosen enough to create a good planting base. It will compact easily. Don’t be discouraged, it will be well worth your time for the success you will have in growing plants and grass and also for the drainage advantages that loose soil in good condition will give you.

There is no doubt about it; working in heavy soil is a pain in the back. It sticks to your shoes and your tools and seems to be a more challenging option than gardening with sand. But with all the hard work, clay soil has its benefits. It has the capacity to hold on to nutrients that your plants need, and it also holds moisture better than other soil types. With some amendments, you can turn your sticky clay into humus-rich, fertile goodness that your plants will thank you for.

Amending Clay Soil

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There is a notion in circulation that adding sand to heavy clay soil with help lighten it. That is a myth, and 99 percent of the time it turns your ground into cement. Soil treated this way becomes so tough that worms can’t live in it. Instead, reach for organic matter, such as compost, leaf mold, and well-rotted manure. Organic matter is the best way to amend clay soil: It lightens the soil texture, discourages compaction, adds nutrients, improves drainage and aeration, moderates soil temperature, and provides pore space, which is essential to plant growth.

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Amending your soil takes some time and patience but rewards you many times over in the end. The first step should be to add as much organic matter as you can and mix it into your existing soil as deeply as possible. Before you start, have a soil test done so that you can incorporate lime, phosphorus, or whatever was recommended at the same time you are tilling in the organic matter. If you are creating a new bed this will be much easier.

Start the process by using a tiller to loosen the existing soil (if it is a large area) or a spade (if it is a more manageable size). Spread about 2 inches of compost on top of the tilled soil and work that in. Repeat the process two more times. Remember to only work in your clay soil if it is relatively dry. Working or walking on wet clay soil seriously damages the structure you are trying to improve.

Working around existing plants will take more time and caution. Autumn is a great time to do this because the weather is generally drier than in the springtime. Another reason you should do this in autumn is that the cooler temperatures are more pleasant to work in, and it becomes an annual part of putting the garden to bed for winter.

Spread a few inches of compost over the ground between the plants and use a narrow spade to turn the compost into the soil. Repeat that at least one more time and plant to make that part of your regular routine. Always work in such a way that you are walking backward and not over your freshly turned soil.

In the long term, regular applications of compost, manure, and other organic matter will continue to improve the structure, tilth, and overall health of your soil. It will become much easier for you to work in and easier for your plants to root in.

One last word on gardening in clay soil: Choose plants that are naturally adapted to growing in clay. It is always better to work with what you have then to try and change it entirely. Happily, for all of us that garden with heavy clay soil, there is an abundance of beautiful plants to choose from.

More On Organic Matter

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  • Emulate how nature works. In wild areas, stems and leaves fall on the ground and rot, amending the soil from the top down. To follow nature’s lead, mulch poor soils with organic matter such as leaves, hulls, or bark.
  • Use what organic material is most available in your region. Whether it’s leaves, pine needles, hulls, or seaweed, it’s all useful for soil improvement. Don’t believe the old myth that pine needles or oak leaves make soil acidic; it’s not true.
  • When using leaves for mulch and amendments, chop them with a lawn mower or chipper. Chopped leaves stay in place, are more weed-smothering, and break down more quickly.
  • Apply top-down soil amendments in layers only 2 or 3 inches deep to allow rain to percolate through.
  • Employ the power of roots to break up heavy soils and add organic matter. Plant marigolds, zinnias, or other annuals in new gardens, cutting them off at ground level at the end of the season. The roots rot in the soil, improving soil structure.
  • By Peggy Anne Montgomery

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