Last Updated on September 6, 2022 by Real Men Sow
There are many charts that can be used to help you with companion planting in your organic garden. Although companion planting charts can tell you which combinations should work together, they do not usually tell you why. How can we be sure that there are benefits of companion planting? This is what we are going to explore in this article.
Benefits of Companion Planting
Companion planting is a gardening technique that involves planting certain types of plants next to each other in order to reap the benefits of their symbiotic relationship. A study of 1,000 companion planting combinations found that certain plants can increase the yield of others by up to 20%.
1. Biological Pest Control
Biological pest control is an option for those who wish to reduce or avoid chemical pesticides. This is based on the use of plants and animals to control pests, rather than chemicals. It is important to remember that the goal of a pest-free garden is not to eradicate all pests. Companion pairs can help protect crops by keeping pest populations low in a variety of ways. Let’s take another look.
Attracting Natural Enemies
Benefits of Companion planting include a visible way to reduce pest damage. It attracts other insects, in this instance predatory and parasitoid species that have a benefit in the garden. It is not surprising that companion pairings increase the number of natural enemies.
You can make natural enemies helpers in pest control by including “insectary” plants in your garden. These are easily recognizable ladybugs and hoverflies. You may not be able to recognize the larval forms of some bugs, so don’t kill one you don’t know.
These helpful insects’ larvae eat pests but the adults eat nectar and pollen. You should remember that not all pests are easily controlled this way. Predatory and parasitoid insect control will work in your favor for controlling the majority of garden pests.
Using The Power of Smell For Deterring Pests
It can help to understand how garden pests are located. One way is through their olfactory or sense of smell. The whiteflies were affected by the slowing effects of limonene, a volatile compound found in marigolds. Mechanical diffusion of limonene also helps. Here are the following studies conducted to help you choose what to grow:
- The roots of African marigolds release chemicals called thiophenes that repel harmful nematodes.
- Rosemary was 18 inches away from sweet peppers and had an anti-aphid effect.
- Alliums (garlic, onions, shallots and leeks) are great in deterring pests.
- Many aromatic species repel pests from brassicas. These include rosemary, hyssop and thyme.
Aromatic herbs can be a useful part of your overall strategy for controlling pest populations. Some of these aromatics can also attract predatory insects, so they will serve double duty.
Making a Visual or Physical Barriers
Pests can also look for their host species visually. As effective as aroma barriers, companion pairings can be used as visual or physical barriers. Crops with other plants are more effective at hiding pests than crops with bare soil.
As physical barriers against pests accessing target crops, taller companions like sunflowers, sesame and sorghum have been successfully used. (Sunflowers can pose problems, but they are not necessarily harmful. More on that later.
Barrier plants are also useful in protecting crops against disease spread by aphids. Monocultures are much more beneficial than polycultures. They allow pests to have easy access to gardens and agricultural areas that contain a wide variety of species.
Trap cropping is another way to use pests’ food preferences for your benefit. This involves knowing the preferences of your local pests, then finding the trap crop that they love and then planting it next to the crop you are trying to protect.
It is better to plant the trap crop before the main crop to give it time to establish itself. This method concentrates pests away from your main crop. The trap should be removed from your garden once it has become infested by pests. Experimenters have used alfalfa to trap cotton, snap beans to trap soybeans, early potatoes to later potatoes, yellow rocket for brassicas, and sunflowers as trap crops for tomatoes. The technique known as “push-pull”, involves trap cropping with repellent species. This repels the pests from the valuable crop and drives them to the trap crop.
Home gardeners who are dealing with severe pest problems should consider planting trap crops with repellent aromatic plants. However, just because you see one or two insects doesn’t mean that you should start trap cropping. It is not the goal to eradicate all pests from your garden. Trap cropping should only ever be used if there has been severe pest damage.
2. Protection and Support
Companion pairings are another way to help with pest control. They can protect and support your main crops by providing shade, water retention, weed control, erosion control, water retention, and structural support.
One of the benefits of Companion planting is that it is a great way to help your main crop. They act as a living mulch and cover any soil that is susceptible to weeds. This will make your garden more productive if you can get ahead of the weeds and plant a cover crop to take over space before they even sprout.
Control Erosion and Better Water Retention
Other than weeds, there are also issues with bare soil. These two problems go hand-in-hand since eroded soil is more susceptible to poor water retention.
Groundcovers planted between main crops can help reduce erosion and improve water retention. Soil-protecting groundcovers can also be very attractive. As a groundcover, I use sweet alyssum, a low-growing, delicately-flowered sweet alyssum interplanted between my vegetable crops. It keeps the soil moist and adds beauty and color that sweat bees as well as other pollinators love.
You can also plant heat-sensitive species under the shade of more heat-tolerant species to reap the rewards of companions. Shade-grown coffee is a new concept and is an environmentally sustainable method of growing coffee.
Even species that are accustomed to the full sun can benefit from shade in hot or dry climates. Lettuce and other leafy greens, for example, can resist bolting if they are grown in the shade of taller vegetables like corn. To help transplants establish, you can also use the shade provided by taller plants. This is a strategy I use often.
Corn and other tall garden vegetables have been used historically to support pole beans in the Native American three-sisters growing method. The corn acts as a trellis and the beans can climb up the corn stalks to anchor it. This helps prevent the corn from being blown away by the wind.
3. Soil Resources
We have looked at the benefits of companion pairing in controlling pests and how it can be used to provide support and protection. This method is also beneficial if you grow groups of plants that share the soil resources (in terms of nutrients and space) rather than competing.
Sharing Soil Nutrients
Polycultures offer another advantage: the members of the mini-community aren’t competing for the same nutrients. This makes soil nutrients more social and less competitive.
There are only so many nutrients in a vegetable plot. Planting only one type of crop will result in all the plants competing for the same nutrients. However, if you plant several crops that have different nutritional requirements and foraging strategies there will be less competition and less nutrient loss.
Heavy Feeders and Light Feeders
While nitrogen is not the only nutrient required by plants, it is the most important element to consider when considering the sharing principle. Some vegetables are known as “heavy feeders”, meaning that they need a lot of nitrogen. Others are called “light feeders” while others are called “light feeders.” Still, other nitrogen fixers are sometimes called “givers”.
This type of companion is legumes. These include clover, alfalfa, and peas, beans. Because legumes don’t take away nitrogen from the soil, they make great growing companions. There are exceptions to this rule, but vegetables grown for their fruits (such as tomatoes or cabbage) are heavy feeders. Vegetables grown for their roots (such as carrot or beet) are light feeders. Corn is one of the heaviest feeders.
Many herbs can also be considered light feeders, which is another reason they are great to have in your vegetable garden. It is important to consider the nitrogen requirements when growing edible plants in your garden. Plan accordingly.
A combination of a heavy feeder and a light feeder, along with a giver, is a great combination. This combination will help reduce the need for nitrogen fertilizers in your garden. Remember that nitrogen isn’t the only plant nutrient necessary for healthy growth.
Because of their differing growth habits, good companions can also share space above the soil in a complementary way. It is very simple logic if you stop and think about it. It would be foolish to plant three root veggies that grow at the exact same rate in the same area – carrots, beets, and potatoes – as they could crowd out each other.
Root veggies like carrots and radishes can be grown together because radishes grow quickly. The carrots will still be growing when the radishes reach harvest time. A complementary combination of carrots, lettuce, and peas would also work well in a square-foot garden.
4. To Avoid Allelopathy
Although many plants can survive and be beneficial to one another in the right combination, there are some that are not so friendly. It is important to understand which plants make poor companions. These vegetative foes can have harmful or allelopathic effects on their neighboring species – this survival strategy is what these species have created to protect soil resources and discourage other species.
The most common allelopathic species are black walnut and sunflower. Both of these species might be found right in your backyard. The sunflower plant’s various parts release chemicals that can be used to stunt the growth of other crops. Instead of planting sunflowers alongside my other garden vegetables, or forgoing them entirely, place them near the edge of my garden so they don’t harm your other edible plants.
Companion Plants Summary
- Insects: Attract predatory and parasitoid insects with nectar, honey, and shelter.
- Repellents are used to repel pests by using olfactory and visual confusion.
- Trap Crops: Attract pests away.
- Nitrogen fixers are soil nutrients that add nitrogen to the soil but don’t compete with this nutrient.
- Light feeders: These plants have lower nitrogen requirements and can’t compete with other light feeders for this nutrient.
- Groundcovers: Act as cover crops to retain water, protect soil, and prevent weeds.
- Shade providers: Provide shade while plants are growing.
- Provide support: Offer a structure to allow other plants to climb on.
- Non-allelopathic species do not contain harmful compounds to other species.
Consider what your crops require, and make sure you choose garden friends that can do multiple tasks. Make sure you choose a variety and utilize these benefits of companion planting to guide you.