Never heard of companion planting before? Companion planting has been going on for many centuries and is pretty much where different species are planted together for mutual benefit. This could be one plant providing shade for another, a neighbouring plant boosting nutrients in the soil or in garlic’s case keeping pests away. Whilst it hasn’t been scientifically proven companion planting is being used more and more by organic farmers in a bid to use fewer pesticides.
Arguably garlic is one of the most reliable plants to grow in your garden. Not only is it relatively easy to grow but it takes up next to no space and improves the soil quality for the plants around it. Due to its pungent scent, it is great at keeping pests away including:
- Cabbage loopers
- Spider mites
- Codling moths
- Fungus gnats
- Even rabbits!
So here’s everything that you can plant with garlic.
- 1. Strawberries
- 2. Spinach
- 3. Cabbage family
- 4. Tomatoes
- 5. Roses
- Allium family
- Planning your garden with garlic: companion planting 28th Oct, 2016
- Growing Great Garlic
- Garlic as a Companion Plant
- Garlic Companion Planting: Plant Companions For Garlic
- Garlic Companion Planting
- Plants That Grow Well With Garlic
- Roses and Garlic
- Marigolds and Melons
- Tomatoes and Cabbage
- Cucumbers and Nasturtiums
- Peppers and Pigweed
- Cabbage and Dill
- Corn and Beans
- Lettuce and Tall Flowers
- Radishes and Spinach
- Potatoes and Sweet Alyssum
- Cauliflower and Dwarf Zinnias
- Collards and Catnip
- Strawberries and Love-In-A-Mist
- Grow onions and garlic
- About onions
- What to do
- Watch video
- Growing tips
- Pests and diseases
- Garden Myths – Learn the truth about gardening
- Garlic, the King of Companion Planting
- Does Garlic Deter Pests?
- Does Garlic Increase Yield?
- Can Garlic be Planted with Beans?
- Garlic May Affect the Target Crop
- Garlic Changes Soil
- Does Intercropping with Garlic Work?
- Is Garlic Intercropping Practical?
The deliciously sweet strawberries are a favourite among many pests but Russian gardeners have discovered that planting garlic nearby keeps pests at bay.
Spinach is almost as hardy as garlic which is why they make great winter companions. Plant garlic in a row or circle around spinach to protect it during cold winters.
3. Cabbage family
The cabbage family (cabbage, broccoli, kale) in particular are susceptible to insect attacks which is why garlic makes a perfect pairing.
Garlic is known for its ability to keep even the nastiest red spider mites at bay.
Roses and garlic are the best of friends. The stinky smell of garlic leaves (which is covered by the delicious smell of roses to the human nose) keeps roses many pests away including black spot.
Planting onions and garlic together won’t have a drastic impact on either crop but it will have a big impact on those around them as like garlic, onions, chives and other members of the allium family repel many mites and grubs.
Although garlic has many friends, it also has a few enemies. Garlic actually inhibits the growth of peas and beans so keep them at a safe distance.
Homegrown garlic takes between seven to eight months to grow, once you’ve harvested the crop you should look at planting something different in the nutrient-rich soil that it has left behind.
You might also like:
How to grow sweet potatoes at home
A guide to homegrown basil
Lemongrass 101: how to grow
Planning your garden with garlic: companion planting
28th Oct, 2016
Why companion planting?
Before planting garlic bulbs in your garden, it’s worth thinking about where you position them, as companion planting can not only help your garlic plants thrive, but also benefit the surrounding plants too! Garlic is a natural deterrent to common garden pests, thanks to the sulphur it accumulates in the garlic bulb, which acts as a fungicide and deters pests such as aphids.
What should I plant garlic with?
When planting your garlic, it’s worth noting that it companions well with the following plants:
- Fruit trees
However, it’s best to keep garlic away from peas and beans as it may stunt the growth of these crops.
How can garlic benefit other plants?
If you want to give your homegrown roses a little extra help, pop a few garlic cloves in the rose beds to help deter aphids, snails, caterpillars and the other insects intent on destroying your lovely flowers. Plant three to four cloves in a circle around each rose bush, and the sulphur present in the garlic will disperse into the soil and be taken up by the rose – making it a less palatable treat for little bugs.
Does garlic produce flowers?
For a beautiful display of curly topped scapes and allium flowers, choose our hardneck garlic varieties, such as Lautrec Wight or Elephant Garlic.
Explore our full selection of hardneck garlic seed varieties
When is the best time to grow garlic?
Growing garlic could not be easier and October-November is the perfect time to plant our Isle of Wight Garlic autumn planting varieties. But if you miss planting garlic in the autumn, it’s not too late for a summer harvest of homegrown garlic: simply choose our Spring-Planting garlic bulbs – such as Solent Wight, Picardy Wight or Mersley Wight, and get them in the ground from January-March. If in any doubt, consult our online Garlic Grower’s Calendar for a breakdown of when to plant different varieties of garlic seed.
Which variety should I choose to grow?
Hardneck varieties have the benefit of producing a curly scape which then turns into a beautiful allium flower – unless you decide to harvest the scapes to eat, as we do here on the farm (The Garlic Farm restaurant serves scapes in a tempura batter, with our Sweet Chilli & Garlic dipping sauce). Elephant Garlic produces huge purple allium flowers which many gardeners plant simply for their beauty. If you’re unsure what type of garlic to grow, try our mixed garlic growing packs for the perfect introduction to garlic growing.
Growing Great Garlic
Garlic can be frustratingly easy to grow. Easy because we just plonk cloves of garlic in the soil. Frustrating because it is meant to be easy but so often we end up digging out tiny bulbs containing even tinier cloves. Here are some hints and tips to growing great garlic.
GETTING GARLIC TO PLANT
Make sure you start with good quality garlic that hasn’t been treated. Garlic sourced from overseas will have been treated to stop it sprouting quickly before export and then with methyl bromide once it reaches Australia by quarantine laws. Even Australian grown garlic may have been treated to slow down sprouting so that it has a longer shelf-life when being sold. This garlic will grow poorly if at all, so don’t bother. Get your garlic from a friend who has grown it, from an organic greengrocer, or from a nursery or accredited farmers market. You can also source it online from the growers or even websites such as Gumtree, Ebay or Farmhouse Direct. Just ask any growers what treatment their garlic may have had before sale.
Prepare the soil before planting. Check your pH. It should be around the neutral mark and if it is lower than 6, add some lime or dolomite to raise the pH. Make sure the soil is friable to a deep level of at least 40cm. Shallow grown garlic will not grow large bulbs. Fork through some compost, or cow manure or other organic manure before planting. Some organic fertiliser such as concentrated manure pellets helps to get the garlic off to a good start. Once the soil is prepared then WAIT for a couple of weeks before planting. Garlic is not a heavy feeder but, like most plants, will appreciate a decent soil to start with.
POSITION AND SPACING
Choose a sunny spot in your garden. It prefers a dedicated bed as it dislikes root competition from neighbouring plants. If you don’t have much space, pop some cloves around your rose bushes to help deter green aphids, or in some larger and deep pots if you are really stuck for space containing some organic potting mix. Shallower pots will result in smaller bulbs.
The soil must be well drained and deeply friable. Garlic roots go down quite deeply and they will not be happy if there is water staying around the roots. Your developing garlic will rot quickly if the soil doesn’t drain well.
Garlic needs a decent chilling period to help develop larger bulbs, so it’s sometimes an idea to put it in the crisper section of your fridge for up to a month before planting, especially if you live in the warmer states.
When planting, separate the bulb into cloves and plant each one individually, about 5cm deep and about 15-20cm apart. If you have more than one row growing, space the rows up to 40cm apart. If you have plenty of space plant them the wider distance apart so that the bulbs have a larger space to develop more fully.
Plant them with the pointy tip upwards. Mulch with some loose straw after planting to a depth of about 3cm of cover. This also helps prevent weeds taking root close by. About a fortnight after planting you will see the green shoots appearing but this may take up to a month for some varieties. If you have garlic waiting to be planted, a tip of when they are ready to go in is just before the green tip emerges from the clove. You often can’t tell unless you cut one open and have a look. (This one will need to go in your cooking after cutting rather than the soil!).
Don’t plant piddly little cloves, as are often found in the centre of certain varieties of garlic bulbs. Use them in your cooking but not for planting. Larger heads will develop into larger bulbs. Straight after planting water in well and then wait.
WHEN TO PLANT*
Traditionally, garlic is planted on the shortest day of the year and harvested on the longest. That may be an easy mantra to remember, but try this instead – plant it earlier and then harvest when it is ready, not when the mantra dictates! Anytime from mid-March up until the shortest day (June 21st) is considered suitable for Melbourne and surrounds. Ideally though, get your garlic in before the end of May. The longer it has growing in cold soil, the better it will develop. You can expect to harvest about 7 to 8 months after planting for most varieties. March may even still be too warm to plant, so aim for no later than April/May to allow for a decently long time in cold soil.
Now this is where things get interesting and I have to admit I’m out of my depth! I do know though, that different varieties have different flavours, heat, keeping powers etc etc. There’s a new world out there if you start getting into garlic, with it being judged just like a fine wine!!
- After planting, don’t ignore the garlic completely. Make sure the soil is kept evenly moist, even throughout winter, as a check in moisture represents a check in growth. If rainfall is inadequate then do remember to water.
- In spring, topping up with a good feeding mulch, such as peastraw, lucerne hay or sugarcane mulch, tucked in and around the plants is a good idea. Don’t dig it in as it will decompose naturally, feeding the bulbs as it does.
- Feeding the garlic after the shortest day (June 21) also helps as the leaves put on more rapid growth. The bulb develops with lengthening daylight hours, so feed fortnightly with an organic liquid feed alternating with liquid seaweed. Continue this regime until just prior to harvesting.
- Keep well weeded as the root competition from the weeds inhibits bulb development.
- In late spring the stalk develops further. At this stage, sometimes you can pull up one or two to enjoy as fresh garlic, or garlic leeks, stalk and all. It is on this stalk that flowers, or more correctly, the umbel may develop, though only on hard neck varieties.
- Harvesting your garlic is best done as the growers do it. They wait to see when the leaves start to brown off. While there are still 4-6 green leaves, they check to see whether the cloves have developed, then wait for a hot dry day and prise the garlic out by lifting them gently. Leave them to dry in the sun for a short while to make the soil easier to brush off.
- Harden the garlic off in a sheltered sunny spot outside until the stalks and leaves have dried off. This may take a few weeks. When the leaves are dried, you can braid them in the traditional way and store in a cool, dry place (mine hang in the garage where they get a cross-breeze). The roots are best trimmed off so that they don’t act as a ‘wick’ for moist air and cause the garlic bulb to rot.
- Keep your best and largest bulbs to plant again next year!
PESTS AND DISEASES
- Black aphids get into the folds of the leaves and burrow into the developing bulbs. Act quickly when first noticed. Use a homemade soap spray to cover the leaves and drip down into the leaves. Then two weeks later, use pest oil; and alternate fortnightly until the problem is resolved.
- Rust is a problem when the garlic leaves are affected in autumn. This happens if the weather is still humid at the time of planting. Leave off planting until May if this is the case. If it happens in spring it doesn’t seem to affect the quality of the garlic. Remove the worse affected leaves. Using eco fungicide prevents further growth of the rust but it doesn’t get rid of existing. Use copper hydroxide if particularly a problem but copper affects soil microbes adversely so it is a last resort. Practice crop rotation.
Try these tips or see if they are any different to how you may have planted garlic in the past. Pulling it up is a very exciting time – especially if they are large bulbs!
* Note that the planting time refers to the southern states of Australia. Northern hemisphere garlic growers will need to add 6 months to the times noted.
Visit The Australian Garlic Industry Association for more information.
Garlic as a Companion Plant
Garlic is an awesome companion plant, it accumulates sulfur, a naturally occurring fungicide which will help in the garden with disease prevention. Garlic also is helpful in pest suppression, it discourages aphids, flea beetle, Japanese beetle, fungus gnats, codling moths, cabbage loopers, ants, snails and spider mites as well as vampires and members of the opposite sex. There is also some proof that it deters mammalian herbivores such as rabbits and deer.
Plants to Avoid Planting with Garlic
It can be advantageously intermingled with most other vegetables and herbs, exceptions are asparagus , beans, peas, legumes, parsley and sage the sulfur it produces is detrimental to their development.
Strawberries are sometimes suggested as a companion plant for Garlic and at other times the recommendation is to avoid intercropping the two. Although it is true that garlic discourages Aphids, spider mites and many other insects and accumulates natural fungicide it is not an ideal companion palnt for Strawberries.
One personal experience of one gardener is hardly scientific proof positive for the record I will state that I tried it once and was disappointed in my Strawberry yield and the flavor also seemed to be adversely effected, perhaps by the sulfur of the garlic. I would advise against planting garlic and Strawberries together.
Garlic is not extremely difficult to grow, but does require some patience. After a long growing season garlic will produce a multitude of bulbs. It is generally planted in the fall, but it can also be planted in the early spring as soon as the ground can be worked. Planting in the fall leads to bigger and more flavorful bulbs when you harvest the following summer and allows more mature garlic plants and bulbs to saturate your garden with their protective properties. See: Growing Garlic
Garlic Companion Planting: Plant Companions For Garlic
Garlic is one of the best companion crops out there. A natural pest and fungus deterrent with few incompatible neighbors, garlic is a good crop to plant scattered throughout your garden. Keep reading for information about the benefits of garlic and the key to successful garlic companion planting.
Garlic Companion Planting
Companion planting is a great low maintenance, low impact way to improve the health and flavor of your garden. Mainly because of the tendency of some plants to repel certain pests, there are pairings you can make when you plan your garden that just work. Garlic, in particular, is something of a wonder plant that improves the quality and health of almost anything it’s planted next to.
Garlic takes up very little space and can grow in most conditions, as long as it has full sun. As a result, it will thrive near plenty of other
plants that may have more specific growing needs and can benefit from its proximity. Garlic is definitely one of the more pungent plants you can grow. Maybe it’s because of this that makes it’s so good at driving away pests. It’s a great deterrent to all kinds of pests including:
- Fungus gnats
- Codling moths
- Spider mites
- Cabbage loopers
- Japanese beetles
- Onion flies
Garlic can even drive away rabbits and deer. If your garden suffers from any of these, try planting garlic next season. It grows best if planted late in the fall, however, so be careful not to miss its planting season. Garlic also naturally builds up sulfur, which is an effective fungicide for neighboring plants.
Plants That Grow Well With Garlic
Because of its many benefits, the list of plants that grow well with garlic is long. Companion plants for garlic include:
- Fruit trees
Flower plant companions for garlic include:
Companion plants for garlic that improve garlic’s overall growth include:
- Rue, which will drive away maggots
- Chamomile, which will improve its flavor
- Summer savory
Though few, there are some plants that actually suffer when planted near garlic. Be sure to keep asparagus, peas, beans, sage, and parsley far away from it, as their growth can be stunted.
Companion planting is a great way to effectively grow plants without the use of any harsh chemicals. Plant companions for garlic and the like will help ensure a bountiful season. Simply intersperse your garlic throughout the garden to maximize its many benefits.
Seasoned gardeners know that a diverse mix of plants makes for a healthy and beautiful garden. Many believe that certain plant combinations have extraordinary (even mysterious) powers to help each other grow. Scientific study of the process, called companion planting, has confirmed that some combinations have real benefits unique to those pairings.
Companions help each other grow and use garden space efficiently. Tall plants, for example, provide shade for sun-sensitive shorter plants. Vines can cover the ground while tall stalks grow skywards, allowing two plants to occupy the same patch.
Some couplings also prevent pest problems. Plants can repel harmful organisms or lure the bad bugs away from more delicate species.
Here are 26 plants that do way better, together:
Roses and Garlic
Oleksandr Berezko/ ; Denis and Yulia Pogostins/
Gardeners have been planting garlic with roses for eons since the bulbs can help to repel rose pests. Garlic chives are probably just as repellent, and their small purple or white flowers in late spring look great with rose flowers and foliage.
Marigolds and Melons
Irina Zholudeva/; tchara/
Certain marigold varieties control nematodes in the roots of melon without using chemical treatments.
Tomatoes and Cabbage
eugenegurkov/ ; thanom/
Tomatoes repel diamondback moth larvae, which can chew large holes in cabbage leaves.
Cucumbers and Nasturtiums
Africa Studio/ ; Nadya N/
The nasturtium’s vining stems make them a great companion rambling among your growing cucumbers and squash plants, suggests Sally Jean Cunningham, master gardener and author of Great Garden Companions. Nasturtiums reputedly repel cucumber beetles, but they can also serve as a habitat for predatory insects like spiders and ground beetles.
Peppers and Pigweed
Yatra/ ; pangcom/
Leafminers preferred both pigweed (also called amaranthus) and ragweed to pepper plants in a study at the Coastal Plains Experiment Station in Tifton, Georgia. Just be careful to remove the flowers before the weeds set seed.
Cabbage and Dill
thanom/ ; Oksana Alekseeva/
“Dill is a great companion for cabbage family plants, such as broccoli and brussels sprouts,” Cunningham says. The cabbages support the floppy dill, while the dill attracts the helpful wasps that control cabbage worms and other pests.
Corn and Beans
Aedka Studio/ ; Thomas Soellner/
The beans attract beneficial insects that prey on corn pests such as leafhoppers, fall armyworms, and leaf beetles. The vines can also climb up the corn stalks.
Lettuce and Tall Flowers
januszt/ ; tecphotoMaine/
Nicotiana (flowering tobacco) and cleome (spider flower) give lettuce the light shade it grows best in.
Radishes and Spinach
Vitamin/ ; Sarah Clark/
Planting radishes among your spinach will draw leafminers away from the healthy greens. The damage the leafminers do to radish leaves doesn’t prevent the radishes from growing nicely underground.
Potatoes and Sweet Alyssum
nednapa/ ; Thirteen/
The sweet alyssum has tiny flowers that attract delicate beneficial insects, such as predatory wasps. Plant sweet alyssum alongside bushy crops like potatoes, or let it spread to form a living ground cover under arching plants like broccoli. Bonus: The alyssum’s sweet fragrance will scent your garden all summe longr.
Cauliflower and Dwarf Zinnias
Esin Deniz/ ; Armei studio/
The nectar from the dwarf zinnias lures ladybugs and other predators that help protect cauliflower.
Collards and Catnip
Elizabeth O. Weller/ ; Katarzyna Mazurowska/
Studies have found that planting catnip alongside collards reduces flea-beetle damage on the collards. The fragrant plant may also help repel mosquitoes.
Strawberries and Love-In-A-Mist
Sentelia/ ; haraldmuc/
Tall, blue-flowered love-in-a-mist (Nigella damascena) “looks wonderful planted in the center of a wide row of strawberries,” Cunningham says.
Grow onions and garlic
Various types of onion, including spring onions, pickling onion and shallots can be successfully grown from sets or from seed, some from both.
Onion sets are small, immature onions, planted in spring or late summer. The sets increase in size and each forms one full-sized bulb when ready to harvest. Where possible, choose onion sets that have been heat-treated. This means their flower embryos have been killed, so they’re less likely to run to seed or bolt. Generally, growing onions from sets is easier and more reliable than from seed and in cooler, damper areas, the sets should give a better yield of larger bulbs than if grown from seed. However the range of varieties available is far greater if growing onions from seed.
What to do
- A sunny, well-drained site is essential for growing good crops of onion and garlic. It’s possible to grow good onions on heavy soil, but the drainage should be improved prior to planting with grit and bulky organic matter, and the cloves planted in ridges of soil 10cm (4in) high to help reduce soil moisture.
- Onions and garlic both like fertile soil, but neither require much nitrogen and so shouldn’t be grown on freshly manured soil. Instead, dig over and manure the ground several months before planting. If the soil is acid it’s worth liming it so its pH level becomes neutral or even slightly alkaline.
How to sow seed
- Sow seed in modules in January or February at 10-15°C (50-59°F).
- Sow five or six seeds per module in damp seed compost – when planted out the clumps of bulbs will push themselves apart as they expand.
- Cover seeds with a layer of vermiculite and label with variety name and date of sowing.
- To have a year-round supply, you can sow once in spring for harvesting from August, and again in late summer or autumn to be ready from June, although a second planting isn’t recommended in very heavy, wet soils. Onions should be given as long a growing season as possible to reach maximum size.
Growing onions from sets
- The easiest way to grow onions is from sets, available from garden centres.
- Prepare the soil a couple of months before planting by digging over and adding manure.
- Plant the sets in spring in shallow drills and cover them so the necks are just protruding from the soil.
- Weed regularly and water sparingly.
- Harvest as soon as the foliage starts to yellow.
In this video Toby Buckland plants onion sets.
- Regular weeding is essential – because of the way their leaves are held upright, onions aren’t good at supressing weed growth and, if left for too long, weeds will soon swamp the crop and cause damaging competition.
- Bolting, or running to flower, can be a common problem with onions, especially if there’s a late cold spell or they suffer hot, dry conditions. Choosing heat-treated sets or late-maturing varieties will reduce the likelihood of bolting.
Harvesting and storage
- As soon as the leaves start to yellow and die back, onions and garlic are ready for harvesting. Don’t bend over the leaves to speed this up.
- Lay the bulbs, complete with foliage, in a warm, dry place for a couple of weeks to dry out. If onions develop thick necks use these straight away as they don’t store well and are prone to neck rot.
- Make sure the foliage is completely dry before storing the crop in a dark, cool, dry place, either by hanging in nets or plaits, or packing carefully in layers in boxes. Storage life depends on the cultivar but is usually 3-6 months.
Pests and diseases
Onions can be prone to various fungus-borne diseases which makes it worthwhile to rotate the position of your onions each year. It’s also worth always buying fresh sets each year from a reputable supplier to avoid the viral diseases that garlic in particular is prone to.
- Onion neck rot – fluffy grey fungal growth around the neck leads to softening of the tissues. Infected areas turn transparent and may start to dry out. Avoid by always purchasing sets from a reputable source and not growing onions on the same site more than two years running. Onions with red or yellow bulbs are less affected than white ones.
- Onion white rot – a dense fluffy fungal white growth around the roots and base of the bulb. If you find it, remove and burn infected plants promptly, and don’t grow onions on the same site for at least eight years. There’s no chemical control or resistant varieties.
- Onion fly – onions are particularly prone to this larval fly but shallots, leeks and garlic may also be attacked. The larvae eat the roots of the bulbs and may burrow into them in late summer. Growing onions from sets reduces the problem, as does interplanting with carrots to mask the smell. If you discover an infestation, remove infested bulbs promptly before the larvae move into the soil to pupate.
- Onion thrips – a fine white mottling on the foliage indicates an attack on onions or leeks. They’re tiny yellow or black bodied insects about 2mm long and are particularly troublesome in hot, dry weather. The damage to leaves can result in smaller crops.
Garden Myths – Learn the truth about gardening
Garlic is one of the most popular companion plants. It can be grown next to most plants as a natural pest and fungus deterrent. It takes up little space, is not fussy about soil and can grow in most conditions.
I am sure that its pungent flavor is what convinces people that it keeps pests and diseases away. If it keeps vampires away, surely a few bugs are not a problem for it.
Garlic – the King of Companion Planting
Garlic, the King of Companion Planting
What are the claims for garlic (Allium sativum)?
Garlic deters pests, including fungus gnats, codling moths, spider mites, cabbage loppers, Japanese beetles and even ants. The pungent flavor of garlic is due to an accumulation of sulfur compounds which are natural fungicides. That explains its ability to ward off disease.
Garlic gets along with most plants, but it should not be grown near asparagus, peas, beans, sage, parsley and strawberries, because it will stunt their growth.
Does Garlic Deter Pests?
A study in Brazil planted garlic, chives, coriander, fennel, oregano, or sweet marjoram in fields of strawberries. They then counted the number of two-spotted spider mites. Tests were done in both the field and in greenhouse settings. Garlic caused a greater reduction (up to 52 %) in strawberry plants when higher populations of two-spotted spider mites occurred in the field. Fennel and chives also showed some reduction.
It is important to note that the pest was not eliminated, and worked best only when pest populations were high.
An interesting study in Zimbabwe compared cabbage planted with garlic to cabbage sprayed with malathion 25WP. They were checking for the diamondback moth. There was no significant difference between the two groups, but counts were higher in a control with no spray or garlic.
A study in China looked at the green peach aphid in tobacco and found numbers were lower with garlic planted, “especially when populations peaked. Other arthropod populations were not negatively affected by intercropping garlic. Species richness, diversity, and stability of the arthropod communities increased.” This seems suspicious. Why was only one arthropod affected?
This study from Botswana intercropped kale with either garlic, basil or marigolds. Basil had the least number of cabbage aphids, but garlic and marigold also reduced the aphid.
A UK study showed that flea beetles laid as many eggs on cauliflowers with or without mint, garlic, dill or sage.
Summary for Pests
These are just some of the studies that have been done. Garlic does seem to reduce certain pests. It has been suggested that garlic releases volatile oils which may confuse flying insects, making it more difficult for them to find their host plant.
If you compare the claimed list of pests with the ones tested in these reports, there is not much correlation. I suspect the lists you find in most gardening sources for companion planting have been made up and repeated so many times that now people believe them.
In order to reach any conclusion about a certain insect, it needs to be tested on the host plant of interest along with garlic.
What happens to beneficial insects such as pollinators and predator insects? If garlic keeps pest insects away it will also keep beneficial insects away. What effect does that have on crops?
Note: A comment was left at our Facebook page when this article was discussed: “My Garlic Farm used to have Aphid outbreaks.”
Does Garlic Increase Yield?
It might repel pests, but does it increase yield. As discussed previously, this is the important question that needs to be asked of any companion planting recommendation.
A study in China intercropped eggplant with garlic and found a slight (2-6%) yield increase (kilogram per hectare). It is not clear if this was statistically significant.
Testing in India showed that garlic planted with sugar cane reduced the sugar cane crop, but the total value of both crops increased.
Research in Egypt showed that strawberry crop yields were reduced when combined with garlic, peppers or snap beans. Strawberries are one crop that is not recommended with garlic.
The evidence that garlic increases yields in not strong. One can assume that if pest damage is reduced, yields go up, but the scientific data to confirm this is limited.
Can Garlic be Planted with Beans?
Apparently these two plants should not be grown together because garlic stunts the growth of beans, but research does not support this. This study did not look specifically for this effect, but it reports the two crops exchanging nitrogen with no indication that beans were affected.
Garlic May Affect the Target Crop
How does garlic, grown beside another crop, change that crop?
This study looked at changes of nutrients in cucumber plants grown with and without garlic, in pots. Nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and manganese (Mn) in cucumber plants were significantly increased while magnesium (Mg) levels were lower. The amount of change was relative to the number of garlic bulbs planted with medium planting showing the biggest benefit.
When Chinese cabbage (Brassica chinensis) was grown with and without garlic researches found that cabbage with garlic had higher levels of soluble protein and nitrate, but sugar content was not significantly affected.
Garlic Changes Soil
A study in China looked at changes in the soil, under plastic tunnels, when peppers where grown either by themselves or with garlic. “Results showed that bacteria population significantly increased in the pepper plot intercropped with normal bulb garlic, while actinomycetes were significantly enhanced in pepper plot intercropped with green garlic. Populations of fungi were significantly inhibited in pepper-green garlic intercropped plots.”
The fact that garlic affects the soil microbes is an interesting fact, but on its own it does not tell us very much about the crops. Such changes may improve the pepper crop yield, or it might decrease the yield, depending on which microbes are affected. What we can say is that the garlic does have an effect on the microbe population in the soil.
This research also looked at enzymes, pH and EC changes in the soil, and concluded that ” intercropping peppers with green garlic improved soil microbial and biochemical properties as compared to monocropping.”
The other interesting aspect of this work is that regular bulb garlic and green garlic (different cultivars of Allium sativum) produced different results.
A very similar study looking at both bulb garlic and green garlic cultivars grown with peppers, report the same results. They also found that intercropping actually increased the NPK in the soil, and concluded that “the intercropping of peppers with garlic enhances the soil fertility by changing nutrient levels, enzymatic activity and the soil microbial population.”
What these last two studies show is that any effect on a crop varies with the cultivar that is used. Not all garlic produces the same results. When companion planting is discussed in books and blogs varieties are hardly ever mentioned.
The claim that the sulfur compounds produced by garlic are a natural fungicide, seem to hold up, at least in the soil. That does not mean they reduce disease above ground.
Does Intercropping with Garlic Work?
The story is much more complicated than implied by popular companion planting text and this question can’t be answered unless we know the crops being discussed. For most crops there is little if any research available, but the yield for certain crops is increased when grown with garlic.
There seems to be some clear evidence that garlic does reduce the occurrence of some pests. But none of the studies that looked at pest populations also looked at yields. Does the reduction of a pest produce higher yields? It is not clear from the data I found.
It seems clear that intercropping with garlic changes a number of soil parameters including both nutrient levels and living populations. What is not so clear is how all of this affects plants. How does the increase in bacteria and decrease in fungi affect crops?
The benefits of companion planting can be a one way benefit or a two way benefit. None of the reports that I found suggested that the garlic crop benefits. This may be due to the fact that the researchers were looking for ways to increase more valuable crops and garlic was not important, or garlic did not benefit.
Is Garlic Intercropping Practical?
Most of the existing research is done in countries other than North America and Europe. It is possible that the interest is greater in countries that have less access to pesticides, are less mechanized and have lower manual labor costs.
Keep in mind that garlic is planted in fall, harvested in mid summer, and peppers are planted in spring and harvested in late summer or fall – at least in zone 5. That complicates an automated process.
This is much less of a problem for the home gardener who does everything by hand.
There is also another practical aspect to companion planting. Most crops have a preferred spacing. How does that change if you intercrop? There is little discussion about this in circles promoting companion planting.
From a home owners point of view there probably is some value in intercropping with garlic. But there is very little concrete information available about which crops benefit. The lists found in popular text on the subject are not based on science. Most recommendations seem to be based on an early book, called Carrots Love Tomatoes by Louise Riotte, which is not science based. Additional information such as crop spacing, and best cultivars is completely lacking.
My feeling is that home owners can consider trying garlic if they have a pest problem, but unless they are trying to solve a real problem, garlic may or may not be beneficial and it might even reduce yield on some crops.
Without careful control testing, opinions from home owners on social media are mostly worthless.
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Wow! The response to this post has been so overwhelming Be sure to also check out Don’t Plant These Together Either | Companion Planting, Part 2
Often times when we talk about Companion Planting we discuss the plants that play nice together and should always be planted side-by-side in our gardens. If you are just Getting Started With Square Foot Gardening, you may want to just plant everything that you want at once.
But there is a catch…..
Not too often do we talk about those plants that just don’t get along. It’s like we are gossiping about the neighbors or something. I mean, even though we love having sunflowers in the neighborhood they sure don’t play well with others. They emit a toxin from their roots that inhibits other plants from growing too close to them as they want all the nutrients in the surrounding soil. Who knew?
Well, I’m here to give you the dish on what plants to NOT plant together when you are companion planting, even if they would look just perfect in your vegetable or herb garden next to each other.
Anything in the bean family, whether it is growing string green beans or bush beans all the way to lima beans don’t get along with quite a few other vegetables. Their biggest nemeses in the garden are chives, garlic, leeks, and onions. They are not fans of bulb-type vegetables (luckily, you can grow many bulb vegetables from kitchen scraps)! Beans also don’t do well with peppers, either the sweet green peppers or their fiery cousins the jalapeños. One plant that I was shocked that beans don’t get along with are marigolds, which are typically crowd pleasers as they deter pests. In fact, all the plants that the bean family shuns are those that deter pests. Go figure!
Peas are cousins to beans and they also loathe the bulb veggies including chives, garlic, leeks, and onions.
Want to know about even more fruits and veggies that don’t like each other? Be sure to also check out Don’t Plant These Together Either | Companion Planting, Part 2
Planting an herb garden? Don’t skip planting these herbs to save you a ton of money!
Both broccoli and cauliflower have a few enemies in the vegetable world. Growing broccoli is really easy and fun, but you want to do it right. They are not fans of peppers, all types of squash including yellow squash and even pumpkins (and yes – this means that if you are growing zucchini, you need to plant them far away). How they don’t care for strawberries or tomatoes I will never know, but they don’t. It seems the cool season crops of broccoli and cauliflower have something against those fruits and veggies that like it a little hotter to grow.
Besides cauliflower and broccoli, steer clear of planting cilantro and cucumbers near tomatoes. Dill and carrots would rather be at other ends of the planter bed too.
So now you know too who would rather stay on their own sides of the garden!
To sum it all up – when companion planting:
- Beans: Don’t plant near chives, garlic, leeks, onions, peppers, marigolds
- Peas: Don’t plant near chives, garlic, leeks, onions, peppers
- Broccoli and Cauliflower: Don’t plant near peppers, squash, strawberries, tomatoes
- Tomatoes: Don’t plant near broccoli, cauliflower, cilantro, cucumbers
- Dill: Don’t plant near carrots
- Sunflowers need to be planted at least 12 inches away from any other plant.
You might want to check out these other gardening tips and frugal living ideas:
- 15 Unique Uses For Baking Soda
- How to Keep Houseplants Alive
- How To Grow an Herb Container Garden
- 15 Amazing Uses For Vinegar
- Basic Rose Care For Beginners
- Natural Pest Deterrents For Your Garden
- 10 Most Popular Vegetables to Grow in Containers
- Square Foot Gardening in Small Spaces