Nitrogen fertilizer for plants

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When you have followed all the rules on the label for your plant but it’s still in poor health it could have a nutrient deficiency.

These occur when the soil is lacking one or more of the nutrients the plant requires to thrive.

Deficiencies often show up in the leaves, which may be discoloured, distorted or dropping off.

The oldest leaves can show problems best where deficiencies have built up, though certain problems, like calcium deficiency, show first in young leaves.

A plant nutrient is any element required for normal growth. The air supplies the essential elements of carbon, hydrogen and oxygen but others are supplied by the soil.

Synthetic or organic fertilisers can prevent or treat deficiencies.

Some sap-sucking insects, fungi and diseases can cause similar problems, so look out for them, too.

And check that you haven’t over or under-watered, which can also cause foliage problems.

Grow healthy plants

Improve your soil by adding well-rotted manure or compost, and spreading organic mulches or leaf mould around existing plants.

Digging it into the soil to a depth of 50mm can help to keep any nutritional problems at bay.

For gross feeders such as citrus, bananas, hibiscus, zucchini and tomato, just use a good quality complete fertiliser designed for that plant. Or target the problem and treat specifically.

TIP Always water plants well before and after feeding.

Feeding pot plants

Plants growing in pots rely on us to keep them healthy. Nitrogen is often lacking, as decomposing potting mix can use it up, keeping it from hungry roots.

Fertilise container-grown plants regularly when they’re actively producing new growth, generally from spring to autumn.

Use a gentle liquid fertiliser or a pelletised organic variety, as salt-based fertilisers can burn confined roots and leave excess salt crust on the pot and mix.

Detecting and treating deficiencies

Look for these symptoms in your plants to identify nutrient deficiencies in the soil. Confirm your diagnosis using a soil test kit before applying the remedy, then treat at the recommended rates.


Older leaves yellow at the bottom of the plant with others pale green. Slow, spindly growth may appear.

TREATMENT Blood and bone, manure and fertilisers containing nitrate, ammonium or urea.

Plants with nitrogen deficiencies have older leaves yellow at the bottom of the plant with others pale green. Image: Getty Images


Leaves turn yellow between the veins and the plant suffers from slow growth.

TREATMENT Epsom salts and dolomite.

If a plant has a magnesium deficiency its leaves Leaves turn yellow between the veins. Image: Getty Images


Dark red-purple leaves with older leaves looking burnt at the tips and poor fruit set.

TREATMENT Phosphate, manure and bone meal.

Plants with phosphorus deficiencies have dark red-purple leaves with older leaves looking burnt at the tips. Image: Getty Images


Yellowing between leaf veins, plus scorched and curling leaf edges and pulpy fruit.

TREATMENT Manure, seaweed extracts and sulphate of potash.

Potassium deficiencies in plants are seen in a yellowing between leaf veins, plus scorched and curling leaf edges and pulpy fruit. Image: Getty Images


New growth is distorted and can yellow and die, and fruit is afflicted with blossom end rot.

TREATMENT Lime, gypsum, dolomite and crushed eggshells.

In plants with calcium deficiencies new growth is distorted and can yellow and die, and fruit is afflicted with blossom end rot.Image: Getty Images


New leaves pale between veins to light green, yellow or white.

TREATMENT Seaweed extract, iron chelates, and ammonium sulphate and compost to lower pH.

In plants with iron deficiencies new leaves pale between veins to light green, yellow or white. Image: Getty Images

Basic understanding of plant health comes from the soil they grow in. Their nutrition is vital to their health and overall sustainability, so it’s essential for plants to get all of the macronutrients necessary to thrive.

However, there are times we still struggle with a plant mysteriously dying off long before its time. It happens, but this is often indicative of a bigger problem with the nutrients in the soil. If one plant is struggling, others nearby may be too.

One method that has worked for me is specifying what nutrients appear to be lacking and why. It’s obvious that plants need nitrogen, phosphorus, and potassium (commonly known as NPK), but plant health is complex and nutrient deficiencies can stem from many places.

1. Nitrogen

Pale yellow, stunted leaves are a sure sign of nitrogen deficiency. Nitrogen is essential in photosynthesis, cell health, and chlorophyll development. Nitrogen depletion in soil happens when large amounts of carbon are added to the soil, typically after nearby plants decay and die. Microorganisms will use available nitrogen to break down the new carbon source and quickly deplete the nitrogen available to the plant. This stunts the plant’s growth.

To correct a nitrogen deficiency, consider planting nitrogen-rich plants like beans and peas nearby. Adding used and rinsed coffee grounds to the soil to promote nitrogen production. Rinsing the grounds will not affect acid levels of the soil. A plant with plenty of nitrogen available to it will appear leafy green.

2. Phosphorus

Phosphorous ensures healthy cell division, fruiting, and root growth. Similar to nitrogen deficiencies, plants with a lack of phosphorus will struggle to grow. The edges of their leaves may darken to a brown or reddish-purple. Flowers or fruits will not grow. Some contributors to phosphorus deficient soil include cold temperatures, heavy rainfall and acidic soil.

To raise soil pH back to a more basic level, add bone meal directly to the soil. In time, the overall growth and color of the plant should return back to normal.

3. Potassium

Potassium is key in a plant’s ability to fight disease and begin fruiting. A plant lacking in potassium will show signs it in its leaves. Potassium-deficient plants will have brown or yellow edges along their leaves.

An effective method to raise potassium levels is burying banana peels an inch below the soil’s surface. It makes sense since bananas are also a rich source of potassium for us!

4. Magnesium

A plant lacking magnesium may look similar to a potassium deficiency. The key difference is that a magnesium-deficient plant will almost always yellow around the edges of its leaves, not brown. Magnesium is a necessary element in chlorophyll, and therefore light absorption for photosynthesis.

To correct this deficiency, sprinkle Epsom salt on top of the soil before watering. Its compound of magnesium and sulfate will replenish the soil.

5. Calcium

A calcium deficiency will be evident in weak leaves that have yellow spots. Sometimes they will even begin to rot. This happens because calcium supports a plant’s structural cell walls, so a plant will gradually weaken without it.

Crushed eggshells are primarily composed of calcium carbonate and can bring calcium back to the soil when buried well into the area around the calcium-deficient plant.

This infographic succinctly details the signs for each deficiency and the natural solutions for each.

Of course, other ways to improve soil quality are by growing diverse number of plants and introducing organic matter and compost. The priority is to always work with nature, aiding when needed, rather than controlling and stopping its natural processes.

Another way to do keep your plant well-nourished is to feed homemade plant food. Homemade plant food is much cheaper than commercial fertilizers and does not contain any added chemicals or fillers store-bought plant food might contain.

Fill an old plastic milk jug with these ingredients and let it sit for about half an hour to let the solid ingredients dissolve. Lightly top your plant’s soil once a month with this solution and adjust your frequency based on how your plants react. Be sure to label the jug and store it where children and pets cannot reach.

Of course, other ways to improve soil quality are by growing diverse number of plants and introducing organic matter and compost. The priority is to always work with nature, aiding when needed, rather than controlling and stopping its natural processes.

Information and photos courtesy of ProFlowers.

Phoslab Blog

By Joseph Mas

Nitrogen is a very important and needed for plant growth. It is found in healthy soils, and give plants the energy to grow, and produce fruit or vegetables. Nitrogen is actually considered the most important component for supporting plant growth.

Nitrogen is part of the chlorophyll molecule, which gives plants their green color and is involved in creating food for the plant through photosynthesis. Lack of nitrogen shows up as general yellowing (chlorosis) of the plant. Because nitrogen can move around in the plant, older growth often yellows more than the new growth.

Nitrogen is also the primary building block for plant protoplasm. Protoplasm is the translucent substance that is the living matter in cells. It is needed for flower differentiation, speedy shoot growth, the health of flower buds and increases the quality of fruit set. It also acts as a catalyst for the other minerals.

In a process called photosynthesis, plants use energy from the sun to change carbon dioxide (CO2 – carbon and oxygen) and water (H2O- hydrogen and oxygen) into starches and sugars. These starches and sugars are the plant’s food. Photosynthesis means “making things with light”.

The primary nutrients are needed for plan growth are nitrogen (N), phosphorus (P), and potassium (K). These major nutrients are usually the first lacking from the soil first because plants use large amounts for their growth and survival. In addition, these elements can leach from soil naturally with the weather especially during rainy or hot seasons.

There are not always enough of these nutrients in the soil for a plant to grow healthy. This is why many farmers and gardeners have their soil tested so they know which fertilizers to use that will add appropriate the nutrients to the soil based on which types of things they grow. Too much nitrogen can cause stability issues, leaching nutrients and over-stimulating top growth. Some fertilizers use a “quick release” formulation that allow for fast greening, but provide for no long term health. Nourishing your garden or lawn strictly from fertilizers like this sends the lawn into a high-stress “starvation cycle.” Many commercially sold fertilizers contain too little slow release nitrogen, if any, or are applied in too large a quantity. The best result for your garden or lawn and the environment are achieved by applying the correct type of nitrogen, in the proper amount, at optimal times throughout the year. How much nitrogen to apply can be found by getting your soil tested. An accurate analysis of the elements in your soil goes a long way for a healthy productive garden and a green lawn.


Most plants grow by absorbing nutrients from the soil. Their ability to do this depends on the nature of the soil. Depending on its location, a soil contains some combination of sand, silt, clay, and organic matter. The makeup of a soil (soil texture) and its acidity (pH) determine the extent to which nutrients are available to plants.

Soil texture affects how well nutrients and water are retained in the soil. Clays and organic soils hold nutrients and water much better than sandy soils. As water drains from sandy soils, it often carries nutrients along with it. This condition is called leaching. When nutrients leach into the soil, they are not available for plants to use.

Balancing your soil nutrients

You might not need much fertilizer in your garden. You may just need to liberate the nutrients already present in your soil with beneficial soil organisms, proper soil aeration, soil drainage, and re-mineralization. For the gardener, this means that organic fertilizers with low N-P-K labels are perfectly adequate for your garden as long as you’re properly caring for your soil. Without proper soil aeration, mineral nutrients, and other factors, your plants may not be able to absorb phosphorous and potassium anyway, so loading up your soil with high levels of phosphorous and potassium may not make much difference with the health of your plants.

Nitrogen is typically available to the soil without additional fertilizers. The trick is having healthy soil full of beneficial microorganisms that can make use of the nitrogen that is available in the air. Earthworm castings and properly prepared compost are teeming with these beneficial organisms. Also, companion and cover crop plants like beans and clover can fix nitrogen that boost soil’s health. Other excellent natural sources of nutrients are fish meal, kelp, alfalfa meal, and bat guano.

Balance is key to a green thumb

Remember, if you have too little nitrogen leaves become yellow-green, the oldest showing yellowing first. Since the plant can move nitrogen, when it is low it takes it from older growth and gives it to newer growth. Growth is reduced, there will be less and smaller fruits.

If the nitrogen is too high then fruits take longer to ripen. Fruit will be soft and have short storage life. Too much nitrogen also hurts root growth and water efficiency of plants. It also will make your plants less tolerant to cold spells.

Get your soil tested by an accredited laboratory

Testing your garden soil is the best way to evaluate the fertility status of your field, garden or high tunnel before planting. A soil test is useful in the diagnosis of plant culture problems, and it is also an important tool in improving the soil nutritional balance. Soil tests will save you money and energy in the long run. The analysis is designed to look for nutrient deficiencies. Knowing then nutrient content in your soil you can then you can amend your soil appropriately based on what you are growing from tomatoes to grass.

Click here for information and to see our garden soil testing service.

10 Best High Nitrogen Natural Fertilizers

Choose the best one for your Organic Garden here…

Nitrogen is one of the most vital major nutrients that plants need.

Sure, you can get a bag of chemical fertilize and throw that around, but in many cases a natural source is more suited to your needs – especially when growing vegetables.

Organic sources are more variable, but also include other micronutrients that your plants require, and in some cases, organic matter which benefits the soil.

Choose from the nitrogen sources listed below for your favorite:

  • Bat guano – one of the best sources of Nitrogen, quick to release.

Great for using mixed with sawdust or other wood product, as the sawdust will tie up Nitrogen from the soil as the microorganisms get to work.

This Nitrogen is released later, as the sawdust decomposes, but in the meantime, without another source of N, your plants will suffer.

Advantages: you only need a bit as it’s so concentrated.

Cons: not sustainable if the bat caves of Peru and other South American countries are depleted and the bats continue to suffer from white nose syndrome, a fatal fungal infection. Some experts fear that the fungus is spread by humans entering caves that are used by bats.

Bat guano is also high in embodied energy – that intangible measurement of the distance that ships and trucks have to travel to deliver it from the source to you. The other options are a much friendlier alternative, such as:

  • Chicken manure; it’s readily obtainable; in fact it can be overproduced if you have a flock of backyard chickens.

The springtime when you clean out the chicken coop can produce a lot of valuable chicken manure, which, like bat guano is a rich source of Nitrogen.

Used judiciously, composted well with the deep litter of the chicken house, this is one of the absolute best of all high nitrogen fertilizers.

Disadvantages: extremely hot in the first stages of decomposition, and can burn tender seedlings with both the heat of decomposition, and the salts that it contains.

Use dry as a top dressing, or mix into the soil well before planting to allow the micro herd to start work on processing it.

Blood Meal

  • Blood meal is a proven high nitrogen fertilizer.

Battle fields are where you can see this particular fertilizer at work.

Abattoirs are the source of commercial blood meal.

Usually dried and purchased as a dark red powder, this product is generally spread around those crops that require a rich soil, or added to slow compost as an activator.

Cons: the smell of blood meal can attract wildlife (like bears) or the neighbor’s dog.

  • Alfalfa pellets – the ultimate legume, chopped and pressed into small pellets has long been used for animal feed.

In the organic garden, each little pellet releases the nutrients slowly over a few weeks to months.

They act as a natural slow release fertilization program for plants that need an extra boost.

Types of High Nitrogen Fertilizer to Avoid;

One day, I noticed that my raspberry canes were looking a little weak. The leaves were yellowing and the fruit was small and sparse.

I made the decision to give them a little pick me up, and sprinkled a generous amount of goat manure, in its tidy little pellets, mixed with the sawdust that was the bedding for the goats.

A while later, the raspberry plants looked better, and I picked the fruit. Which tasted awful! The taste of goat in the fruit made them the worst I’ve ever tasted.

The absolute best type of fertilizer for raspberries is LOF, applied in the dormant stage, early in spring maybe, or after the fruit is harvested.

  • Horse manure is one of the best natural fertilizers.

The fact that horses only have one stomach makes it impossible for them to completely digest the hay and green fodder, leaving a good percentage of smaller particles that can add valuable organic matter to the soil.

A disadvantage of this process is that they also don’t digest seeds of the weeds that they eat, and those germinate and grow wherever fresh horse manure is spread.

It’s absolutely imperative to compost horse manure properly (ie: by allowing the heat to build up and kill weed seeds) before use. The only time you don’t need to do this is when using fresh horse manure in compost tea.

  • Compost tea – my favorite brew.

I make compost tea with anything available; alfalfa pellets or meal, dried weeds, horse manure, or even compost.

Add a couple of shovels full of compost to a nylon stocking, and immerse in a large trash can full of water, stir daily for a week or two and dilute before using.

Avoid using compost tea on leafy green crops that you will eat raw, as it can be a source of E. coli or other digestive problems.

Fish Fertilizer

  • Fish Fertilizer – This is made from ‘junk’ fish, or menhaden. These small fish are bony and inedible, so they’re used for fertilizer.

Fish, planted whole in the same hole for a plant, have been used for millennia, so this is not new.

Use caution with fish fertilizer. When they tell you to dilute it, don’t think that if a little is good, more will be better. This stuff is strong, and will burn plants. It also smells terrible. Don’t use it on house plants, or anywhere near your house. It can attract bears, if you live in bear country.

  • Liquid organic fertilizer – the most useful of all natural fertilizers.

Guaranteed that the source will never run dry, and it can be used on most crops with the exception of leafy greens, for a similar reason to compost tea, and also for the ‘yuck’ factor.

What is it? Human urine is a high source of urea, which is broken down into nitrogen.


  • Seaweed and kelp are harvested from beaches after a storm, and composted or dried and used as mulch.

Harvesting commercially in large quantities is not a sustainable practice, but if you live near the ocean, take a couple of garbage bags with you when you go beach combing.

Rinse well to remove the salt before you put it on your garden.

Other sources of similarly valuable water weeds are Eurasian Milfoil, dredged from lake bottoms or water hyacinth, a rampant grower in warmer areas.

Cut it up into small pieces so it breaks down quickly, use as a mulch, or compost it.

  • Air – no kidding, you can get nitrogen from the air, as it is gathered by rain and snow falling.

Snow is known as the poor farmer’s fertilizer due to this.

This list gives you plenty of options for high nitrogen natural fertilizers to use on your organic garden. Choose one or two, and see the results.

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Compost and manure are excellent nitrogen sources that also improve soil.

Nitrogen is a very important nutrient for plant growth. It encourages lush growth of leaves and stems as well as providing a dark green color to the plant. Nitrogen is particularly important for lawns and other plants that are primarily grown for their foliage. Plants lacking in nitrogen will be spindly and yellowish.

Most chemical sources of nitrogen are made from processed fossil fuels; but there are plenty of natural, organic options available that work just as well. Organic sources of nitrogen are a little trickier, since the amounts – and speed of uptake – vary from one type of material to another. However, organic amendments and fertilizers are often much more forgiving than their chemical counterparts, making it harder (though not impossible!) to over apply and damage plants.

Organic sources of nitrogen for your yard and garden include:

    Blood meal fertilizer.

  • Alfalfa Meal: This product contains not only nitrogen, but phosphorus and potassium. Alfalfa meal encourages beneficial microbes and is an excellent organic source of nitrogen.
  • Animal Manure: The waste from grass eating animals is an excellent source of nitrogen. Make sure the manure is well composted; since raw manure can not only burn your plants, but the nitrogen is more volatile and can leach away. Also, composting at a high temperature for an extended period of time can generate enough heat to kill weed seeds present in the manure.
  • Blood Meal: Made from the waste of slaughterhouses, blood meal is a potent source of nitrogen than can burn your plants if over applied, especially on young seedlings. Because it’s water-soluble, blood meal can be mixed with water or applied through your irrigation system.
  • Cottonseed meal fertilizer.

  • Compost: Organic compost contains all of the nutrients essential for healthy plants, including nitrogen. Although the exact dosage varies depending on what was composted, overall the product is one of the best ways to enrich and improve your soil.
  • Cottonseed Meal: This organic source is slightly acidic and provides nitrogen in a fairly slow-release form.
  • Feather Meal: Chicken feather meal is often dried and formed into pellets which make an easy to use granular fertilizer. Feather meal has a moderate release rate, as soil microbes break down the proteins to make the nitrogen available to plant roots.
  • Fish Emulsion and Fish Meal: These sources of nitrogen are made from the processed waste of the fish oil industry. Fish fertilizer products are very fast acting, especially if applied in liquid form.
  • Fish emulsion fertilizer.

  • Green Manure: Cover crops – such as alfalfa, clover, peas, and other legumes – are able to absorb nitrogen from the air and release it into the soil. Growing these cover crops in your garden improves the soil just by living in it. Tilling cover crops into the ground at the end of the growing season results in a double dose of nutrients and natural compost. If you rotate crops in your vegetable garden, be sure to add green manures to the rotation cycle.
  • Soybean Meal: Similar to cottonseed meal, soybean meal is a slow release source of nitrogen made from ground soybeans.

Further Information

  • Fertilizer 101 (article)
  • The Debate over Organic vs. Chemical Fertilizers (article)
  • Organic Sources of Potassium for Your Lawn or Garden (article)
  • How to Use Fish Fertilizer in Your Garden (article)
  • How to Green Up Your Lawn with Iron Supplement (article)
  • Choosing Fertilizer for Your Lawn or Garden (video)

Adding Nitrogen As A Plant Fertilizer

Your garden isn’t growing as well as it used to and some of the plants in the garden are starting to look a little yellow. You suspect a nitrogen deficiency in the soil, but you are unsure how to correct it. “Why do plants need nitrogen anyway?” you may be wondering. Nitrogen as a plant fertilizer is essential to proper plant growth. Let’s look at why do plants need nitrogen and how to correct a nitrogen deficiency in the soil.

Why Do Plants Need Nitrogen?

To put it in simple terms, plants need nitrogen to make themselves. Without nitrogen, a plant cannot make the proteins, amino acids and even its very DNA. This is why when there is a nitrogen deficiency in the soil, plants are stunted. They simply cannot make their own cells.

If there is nitrogen all around us, as it makes up 78 percent of the air we breathe, you may also wonder why do plants need nitrogen if it is everywhere? How is nitrogen made accessible to plants? In order for plants to use the nitrogen in the air, it must be converted in some way to nitrogen in the soil. This can happen through nitrogen fixation, or nitrogen can be “recycled” by composting plants and manure.

How to Test Nitrogen of Soil

There is no homemade way how to test nitrogen of soil. You will either have to have your soil tested or purchase a soil testing kit. Typically, your local extension office will gladly test your soil for a small fee or even for free, depending on where you live. When you have your soil tested at the extension office, they will also be able to tell you any other deficiencies you may have.

You can also purchase a kit as a way how to test nitrogen of soil. These can be found at most hardware stores and plant nurseries. Most are easy and quick to use and can give you a good idea of the nitrogen content of your soil.

Fixing a Nitrogen Deficiency in the Soil

There are two routes to go when fixing a nitrogen deficiency in the soil, either organic or non-organic.


To correct a nitrogen deficiency using organic methods requires time, but will result in a more even distribution of the added nitrogen over time. Some organic methods of adding nitrogen to the soil include:

  • Adding composted manure to the soil
  • Planting a green manure crop, such as borage
  • Planting nitrogen fixing plants like peas or beans
  • Adding coffee grounds to the soil


Nitrogen as a plant fertilizer is common when purchasing chemical fertilizers. When looking to specifically add nitrogen to your garden, choose a fertilizer that has a high first number in the NPK ratio. The NPK ratio will look something like 10-10-10 and the first number tells you the amount of nitrogen. Using a nitrogen fertilizer to fix a nitrogen deficiency in the soil will give a big, fast boost of nitrogen to the soil, but will fade quickly.

Nitrogen is absolutely vital for plants, and boosting this nutrient in your soil will help you grow healthier flowers, herbs, and vegetables. There are many organic methods you can use, which we’ll cover in this your complete beginner’s guide on how to add nitrogen to the soil.

Why Your Plants Need Nitrogen

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Nitrogen (N) is essential to plant growth. Without it, they wouldn’t be able to create the protein and amino acids they need to survive. Even a plant’s DNA depends on this element, as it helps to create new cells.

Although nitrogen is in the air around us, plants access it through the soil. Thus, beginner gardeners need to learn how to convert nitrogen into the soil for the best results in plant growth. There are two main ways to do this: nitrogen fixing, or composting. Both are natural ways to add this vital nutrient without using harsh chemicals.

Nitrogen fixation is essential to allow photosynthesis to happen. There are bacteria that use the nitrogen in the air to convert it into a solid that plants can use. You can increase the number of these bacteria in your soil by planting crops like beans, peas, or other legumes (more on this later).

Create Homemade Fertilizer

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In contrast, composting involves creating fertilizer at home so you can add vital nutrients to the soil each year. However, fertilizer will only feed your actively growing plants, while compost adds nutrients directly to the soil. The latter is the best way to grow the healthiest plants over long periods of time.

Instead of buying a large bag of potting mix from your local garden center, add your own compost to the soil. This will promote plant growth, as well as allowing you to recycle biodegradable waste such as leaves or vegetable scraps.

A nitrogen-rich compost as bacteria and other symbiotic life forms that allow veggies to feed themselves, fight off diseases, and boost flavor. In addition, compost allows soil to retain moisture levels. You can purchase bagged compost, but a homemade version is the best source of nitrogen.

If you’ve never made your own compost before, you can learn how to make a pile at home. Alternatively, you can purchase it from a garden supply store. Many gardeners choose to make their own for small projects, and buy commercial compost as needed for large-scale grows.

How to Tell if Your Soil Needs Nitrogen

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A plant with a nitrogen deficiency will grow stunted and smaller than normal. Because they can’t make their own cells without nitrogen, plants won’t grow to their full potential without it.

Leaves or foliage turning yellow is the first sign of a nitrogen deficiency in most plants. You may also notice less flowering or fruits, and your plants may appear thin or pale.

How to Test Nitrogen Levels

The only way to test the nitrogen levels in your garden is with a soil-testing kit. You can pick one up from your local plant nursery or hardware store, or you may find a service test the soil for a small fee.

The kits you can buy yourself are quick and easy to use, but they only focus on nitrogen. A professional horticulturist can let you know what other deficiencies your soil suffer from.

How to Add Nitrogen to Soil to Fix Deficiencies

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You could purchase a chemical fertilizer to boost nitrogen levels, or you can take advantage of the many organic amendments. Organic methods on how to add nitrogen to soil take more time, but they will typically maintain an even level over a longer period of time.

Banana Peels

You can add banana peels to the bottom of your compost pile, or you can add them directly into a flower bed before you plant. After you dig each hole, place the peels in and allow them to degrade for a few days before you plant your flowers.

Coffee Grounds

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If you enjoy a morning espresso, save the grounds to reuse them in your garden. Even if you don’t enjoy drinking coffee yourself, you can collect coffee grounds from a nearby coffee shop. You can even ask a neighbor for theirs.

Coffee releases nitrogen into your soil, as well as magnesium, potassium, copper, and phosphorus. It also helps keep pests like slugs and cats away, while attracting beneficial earthworms. There a few ways you can use coffee grounds to add nitrogen to your soil:

For a quick boost, sprinkle your used grounds directly onto the soil in your potted plants or raised garden beds. Water the grounds into the soil or add them to outdoor plants just before it rains.

Or, you can add the grounds to your compost pile to boost nitrogen levels. The grounds quickly break down when mixed into compost, and unwashed grounds will often lower the pH balance of your soil. This helps acid-loving plants like tomatoes and berries thrive.

Lastly, make a diluted, weak coffee infusion using your old grounds and water the plants directly with the liquid. Wash the coffee grounds for a more neutral pH balance, or use them as is for more acidic soil.

Fish Tank Water

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Fish manure, which is high in nitrogen, potassium, and phosphorus, is a great natural fertilizer. After cleaning your fish tank, save the old water in a bucket and use it to feed nutrients to your plants. However, don’t ever use the method in conjunction with fish antibiotics, or any other medicine for sick fish. You’ll kill your plants.


Allow old eggshells to dry, crush them, and add them to soil or your compost pile for a slight nitrogen boost. The amount of nitrogen this method produces is low, but adds a decent amount of calcium to your soil.

Fireplace Ash

You have to clean out the fireplace anyway, so use the wood ash to add nitrogen to your soil. Don’t scatter the ashes on a windy day, however, or you’ll end up eating them. Additionally, don’t layer the ash more than 1/8 inch thick, as any more will create a paste when it gets wet.

Weeds and Legumes

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Plants in the legume family naturally convert airborne nitrogen into a compound that plants can use. As a result, planting crops like beans and peas as companion plants will help heavy feeders like asparagus or corn. Weeds like nettles or burdock also work well as natural plant fertilizers.

Grass Clippings

Adding grass clippings from your yard to your compost pile is a free, easy way to add nitrogen and potassium. You can use a mulching mower to collect the clippings easily, or rake after you mow the yard and shovel them directly into your garden. Add the clippings around the base of your plants in multiple thin layers.


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If you have herbivorous animals at home, you can use their manure to create a rich nitrogen additive for your soil. Fresh manure contains too much nitrogen, however, whereas 6-month-old manure is more easily absorbed. The best animals for this process include:

  • Rabbits
  • Sheep
  • Cows
  • Horses
  • Ducks

Manure also adds nutrients like phosphorus and zinc, and you can purchase it from a garden center as well. Protect yourself from illness by always wearing gloves when handling animal waste. Also, make sure to wash your hands well when you’re done.

Human urine

It may sound gross, but human urine works extremely well as a plant fertilizer. It’s sterile, and as long as it comes from a healthy person, can be added to a compost pile to add more nitrogen than a store-bought fertilizer. However, the urine must be diluted or it will burn the plants. Try one cup of urine to eight cups of water for the best results.

Food Waste

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Plant-based food scraps that normally wind up in the trash can instead be added to your compost pile to enrich the soil with nitrogen. The process takes several months to complete, so begin during the early summer to have compost ready for next spring. The best food waste to add to your compost include:

  • Tea leaves
  • Stale bread
  • Corn cobs
  • Fruit rinds
  • Veggie scraps
  • Nutshells

Follow our guide on what NOT to add to compost to learn what does and doesn’t go into a healthy compost pile.


Create a leafy mulch before winter strikes by scattering 2-4 inches of leaves over your garden. After all the plants have been removed from your garden patch, add the leaves, and water them to keep them in place. They’ll break down during the winter, feeding your soil with nitrogen so it’s ready for summer planting.

You can also add leaves to your compost pile for the same results. Just make sure they’re dry before adding them to the compost to avoid unpleasant decomposition odors.

Chemical Fertilizer

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Chemical fertilizer from your local garden is a quick way to boost nitrogen. It’s an easy treatment for nitrogen deficiency, but the benefits will fade much quicker than the aforementioned organic methods. To find the right fertilizer for your needs, look for a 10-10-10 N-P-K (Nitrogen, Phosphorous, Potassum) ratio.

Finally, additives like bone meal, blood meal, kelp, or fish emulsion can be helpful. They work as great chemical-free ways to add nitrogen-rich fertilizer to your plants.

However, the best organic method depends on the type of foods you normally purchase. If you eat a lot of eggs, bananas, and veggies, you should be able to create enough nitrogen from their scraps alone.
The result is less trash for you to throw out, and a healthier garden overall.

Your garden has been growing for years, but your plants seem to be struggling more than you used to. Or maybe you’ve planted veggies in your usual spot this year, but they don’t seem to be thriving as they have in years past. If these scenarios sound familiar, you might be facing a nitrogen shortage in your soil.

Nitrogen is a chemical element that’s essential in gardening. It encourages plant growth and helps provide foliage with its green coloring. Healthy soil contains and requires this crucial nutrient to thrive.

Have you ever wondered what the numbers on a bottle or pack of fertilizer mean? In fertilizers, NPK refers to the three most crucial macronutrients required by plants: nitrogen, phosphorus, and potassium.

When we add fertilizer, we’re replacing these nutrients in the soil. As they grow, your plants draw out nutrients that aren’t being replenished. Plants need these nutrients to survive, so unless you put back what the plants are taking out, your veggies will begin to starve. The bottom line is that without nitrogen, your plants can’t grow.

That said, not all vegetables and plants require the same amount of nitrogen, so you can’t just feed and forget. Different plants have different needs. Some plants, like tomatoes, are heavy feeders. While others, like lettuce, are light feeders. Some plants even put some nitrogen back into the soil.

What are the Signs of a Deficiency?

Because plants take up nutrients from the earth, it’s essential to replenish the soil’s supply. Your garden won’t thrive if you don’t replace the things that are being taken out.

Typically, you need to add nitrogen to the soil if there is a deficiency or your plants are hungry and require a lot of nitrogen to flourish. So how can you spot a deficiency? A typical sign is stunted growth or yellowing leaves, but these may also be a sign of disease or pest infestation.

Even experienced gardeners may have trouble diagnosing potential nutrient deficiencies. It’s best not to play a guessing game. Soil testing should be your first step before addressing any nutrient imbalance in the soil.

What Happens When You Have Too Much Nitrogen?

Why not add as much nitrogen as possible? The more, the better, right? If it encourages growth, large quantities should make your plants big and strong! Unfortunately, that’s not the case. Too much nitrogen may leave you with big leafy plants that won’t bear any vegetables or fruit.

Potatoes and tomatoes grown in soil abundant in nitrogen, for instance, will produce few taters and tomatoes but will have an abundance of leafy green growth.

Another reason to avoid adding too much nitrogen to your soil? Soil contamination may occur if excess nitrogen is present. The excess nitrogen may leach into and pollute nearby water sources.

How to Add Nitrogen to Soil

Before you start adding nitrogen to the soil, perform a soil test. If you have a lot of nitrogen at the start of the gardening season, there’s no point in adding a ton more. Know your soil’s composition before adding any fertilizer. Once that’s done you can get to adjusting your nitrogen levels.


Fertilizer is the most obvious way to add nitrogen to your soil. Choose an appropriate fertilizer with the correct NPK ratio for your needs. There are a variety of synthetic fertilizer options with high nitrogen concentrations, but compost is an excellent non-synthetic alternative that provides a slow release of nutrients. Regularly amending the earth with compost helps to build healthy soil, which in turn will experience fewer incidences of deficiency. It’s a win-win situation.

Nitrogen-fixing crops

These are crops like beans and legumes. Instead of taking up nitrogen they fix the nutrients in the soil. Grow beans and legumes in areas where you previously grew nitrogen-hungry plants the year before. Avoid fertilizing areas where bean crops were grown in previous years since there’s no need for the added nitrogen.

Cover crops

Crops like clover are also nitrogen fixers. The difference is that you’re not growing them to harvest. Usually, you plant at the start of the season or in the off-season. The downside of this method for home gardeners is that it takes significant effort to remove cover crops and begin planting. If you’re thinking of growing cover crops to suppress weed growth, consider plastic mulch to do the job instead.

Grass clippings

If your lawn is deficient in nitrogen, grass clippings are an excellent way to address the problem. When you mow your lawn, let the grass clippings – so long as they are an inch or shorter – return to your lawn. They will gradually increase nitrogen levels over time.

You can also sprinkle glass clippings around your garden as a mulch that can add a little bit of nitrogen.

Busting Myths About Nitrogen

There are plenty of natural fertilizer options like coffee grounds and egg shells floating on the internet, but are they all useful sources of nitrogen? Let’s take a look at the most popular suggestions:

Coffee grounds

The leftover grounds from your coffee are an excellent compost additive but are relatively useless and potentially harmful when added directly to garden soil. If you want to re-use your coffee grounds, add them to your compost first.

Fish emulsion

Fish emulsion is another natural soil amendment, but it contains low concentrations of nutrients, so it’s not necessarily an ideal candidate for dealing with a severe deficiency. It’s an excellent option for smaller jobs like feeding seedlings and transplants, though.

Egg shells

Eggshells are a popular kitchen scrap that people love to throw in the garden. I prefer to toss them into the compost pile, but is there any use to adding them to the garden to address a nitrogen imbalance? Sure, egg shells do contain slight traces of nitrogen, but the small amounts are negligible and won’t make much of a difference if you’re experiencing a severe nitrogen shortage. You can use them to ward off pests, however. Crushed eggshells keep slugs and snails from getting too close to your greens and nibbling them until there’s nothing left.

Dog or human waste

Have you heard of this option for adding nitrogen to the soil? Don’t even think about it. First, any animal waste should be composted before use in the garden, and it’s a terrible idea to stick your own or your dog’s feces into the compost. You’re likely to spread disease and contaminate your food supply. You may be able to add dog waste to your city’s brown bin, but find out if it’s allowed before doing so.


You might have heard that urine is an excellent source of nitrogen. I’d suggest saving your pee for your next outdoor adventure. If you’re really feeling wild, you can enjoy it Bear Grylls style. All kidding aside, don’t start collecting pee jars for your garden. Not only is it gross, but it’s also a lot of effort for little payback. Concentrated urine can kill your plants. I’d advise against it, especially since not all urine is necessarily free of bacteria and viruses.

The bottom line is while most of these options may alter your soil slightly, none of them is the answer for how to add nitrogen to soil. Most natural nutrient sources are most effective when added to compost and then worked into the soil.

Be Cautious with Fertilizer

Take care when attempting to alter the nutrient balance of your soil. Throwing things out of whack may cause pH imbalances, pollution of nearby water sources, and if your soil isn’t healthy, you’re likely to experience high incidences of pest and disease.

Adding excess nitrogen in an effort to curtail future deficiency is a poor choice, too. Some plants respond poorly to high levels of nitrogen and won’t produce fruit. It’s also a wasteful endeavor. In some cases, another imbalance may lead to an inability for plants to absorb the nutrient. If the pH of your soil is off, for instance, plants may not be able to access nitrogen in the soil, so adding more isn’t going to solve the problem.

Are you facing a nitrogen challenge in your garden this year? Let us know what option you choose for addressing it and how it works out.

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If your soil starts to lack the Nitrogen it needs – you will need to add a high nitrogen fertilizer as soon as possible. Since Nitrogen is a core nutrient required for plant growth, ensuring you have the appropriate amount is critical. In this article, we will discuss the effects of a nitrogen deficiency and how to increase nitrogen in soil.

Effects of low Nitrogen levels soil

Nitrogen deficiency in your plants can be most commonly identified by:

  • Yellowing of your leaves (chlorosis)
  • Lack of flowering and fruits
  • Plants look thin and pale

Once you determine that in fact your soil is lacking nitrogen, there are 2 paths you can go: organic or inorganic(synthetic).

I always choose organic as my first choice, but I understand it is not always feasible. Let’s now look at ways we can increase nitrogen in soil.

Correcting A Nitrogen Deficiency Organically

Luckily, there are plenty options if you enjoy keeping things organic. Here are 4 methods to increase nitrogen levels in your soil:

  • Manure – adding manure is one of the simplest ways to amend your soil with nitrogen. Be careful as there are various types of manures with varying degrees of nitrogen.
  • Coffee grinds – use your morning addiction to feed your gardening habit! Coffee grinds are considered a green compost material which is rich in nitrogen. Once the grounds break down, your soil will be fed with delicious, delicious nitrogen. An added benefit to including coffee grounds to your soil is while it will compost, it will also help provide increased drainage to your soil.
  • Plant nitrogen fixing plants – planting vegetables that are in Fabaceae family like peas, beans and soybeans have the ability to increase nitrogen in your soil
  • Plant ‘green manure’ crops

Correcting A Nitrogen Deficiency with Synthetics

The simplest way to treat a nitrogen deficiency inorganically is by using chemical fertilizers. Some of the large brand names that you are probably aware of are names such as Miracle-Gro. In order to select the correct fertilizer for your needs, you first need to understand fertilizer basics.

You want to select a fertilizer that contains the higher first number that you see on the bag. For example, you will see a series of 3 numbers(e.g. 15-10-10) that represent the various compounds in the fertilizer. The first one is the nitrogen concentration, which in this case is 15%. This means it will be fertilizer that is high in nitrogen.

As you can see, nitrogen deficiency effects can sometimes be easily identifiable, but sometimes not so much. If you want to be sure that you soil has a nitrogen deficiency, a soil test kit will provide you a concrete result on the issue you’re facing. Think of it this way, if you’re sick you go to the doctor, you don’t try to diagnose it yourself without concrete evidence. This is the ONLY way to guarantee what you’re dealing with.

If you have any other questions that I can help out with, please feel free to ask a question below in the comments section.

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