When gardening, we can use all the help we can get. There is more to a successful garden than just following the instructions on the back of the seed pack. Each plant is not an island, and you can boost your productivity by combining a mix of plants that compliment each other.
Gardeners have learned a lot of nuances about growing over the last few centuries, and you should take advantage of this knowledge.
What is Companion Planting?
This isn’t gardening with your friends. It’s an age-old technique of pairing up certain plants that seem to grow better together.
Sometimes it’s because one plant tends to repel the pests of another, or it might be due to the way each plant changes the soil chemistry that helps other plants too. These techniques are most commonly used in outdoor vegetable gardens, but the general idea would work with any kind of plants as well as indoor houseplants.
Once you know the details of great plant companions, you can use this information to map out new layouts to keep the right plants near one another.
Not all companion pairings are just 2 plants that work together. Quite often, you’ll find one group that would work well with any plants of another group. That means you have some room to mix and match plants to suit your garden needs.
What are the Benefits of Companion Planting?
One of the biggest reasons to companion plant is to help with natural pest control. Plants don’t just keep insects off themselves, they can offer some expert assistance in keeping bugs away from nearby plants as well.
Garlic with Anything
When you’re looking to get rid of bugs, adding garlic around any plants is a good idea. The pungent smell puts off insects, and can also repel larger pests like squirrels, rabbits or even deer.
Mint, Sage and Rosemary with Cabbage
Actually, mint, sage and rosemary partner well with the entire Brassica family (cabbage, cauliflower, broccoli, kale). The herbs are known to repel the cabbage moth, which lays eggs that eventually hatch to release the devastating cabbage worm.
Dill with Tomatoes
If you are growing tomatoes, you simply must have a few dill plants mixed in. The sharp smell of dill will keep tomato hornworm away from your plants.
Asparagus and Tomatoes
Yes, tomatoes again. Their unique chemistry (part of the nightshade family) makes them suited for several different companion arrangements. In this case, they go well with asparagus in a perfect win-win situation. The asparagus drives away certain nematode worms that target tomatoes, and the tomatoes repel asparagus beetles.
Beans and Potatoes
Beans will repel the notorious potato beetle and potatoes are known to keep bean beetles away. Plant in alternate rows to make the best use of this pairing.
Nasturtiums with Anything
Nasturtiums are annual flowers that are very attractive to aphids. Instead of taking a repellent approach, you deliberately “sacrifice” your nasturtiums to help protect nearby plants that are bothered by aphids. It doesn’t help the flowers any, and are referred to as a trap crop when used this way.
This is a great companion approach for houseplants too. A few pots of nasturtiums will keep any indoor aphids from attacking your other plants.
Radishes with Cucumber
This is another trap crop maneuver. Radishes will attract several insects like the flea beetle that normally are a problem with cucumbers. You don’t even have to worry about picking them. Let the radishes keep on growing right until they go to seed, and you have beetle protection for your cucumbers all season long.
Any plant companions that go with anything should be planted interspersed among the other crops, and not necessarily matched up with any one type of plant.
Shade, Space, and Support
There are other reasons to work with companion planting besides insect control. Here are some handy pairings that are all about efficient use of space, creating shade or adding support to your garden plants.
Lettuce and Squash or Pumpkins
Big sprawling vines of squash or pumpkins put out large leaves and tend to shade out a lot of weeds. It can also be a handy place to plant cool-weather plants like lettuce. Once your pumpkins are well established with big leaves, get some lettuce seeds in the ground nearby to take advantage of the shade and new little micro-climate.
You can use this shading pairs technique with houseplants too. It’s especially helpful if you have limited window space to work with. For a south-facing spot that has too much sun for some shade-loving plants, have one or two bigger plants in there that do love the heat, and let their shade keep your other houseplants cool.
Corn and Pole Beans
This is the most classic example of a support-based companion plant pair. Plant pole or runner beans, the kind that put out long vines, at the base of your corn plants, and let the beans grow up the corn stalks for natural support. The corn doesn’t benefit really but letting the beans grow this way doesn’t do it any harm either.
You can also use corn as a support for vining cucumbers, as long as they don’t produce really large fruits that might be too heavy for the corn stalks to handle. An added benefit of pairing cukes with corn is that raccoons may be deterred by the mass of slightly prickly vines, and that can protect your corn.
Radishes and slow-growing crops
Radishes are super fast growers, and can be paired up with any other slow-growing crop to maximize the use of your space. It’s not necessarily going to make either plant grow any better, but this sort of arrangement means you can get 2 harvests from the same spot of garden territory.
Plant your seeds at the same time, and you’ll be picking radishes before the other crops are getting huge and need the space. Plants like squash, pumpkin or potatoes or even carrots would work well here.
Beans and Brassicas
This is a little different than the others, in that it’s a pairing that has to do with nutrients in the soil. Beans and other legumes (like peas) will fix the nitrogen in the soil, and this can be very helpful for other plants like broccoli, cauliflower and kale.
You can either plant them intermixed in the same patch, or take a different approach and grow beans in one area, and then change it to a Brassica crop the next year. The improvements to the soil will last from one season to the next.
Carrots with Tomatoes
This is a classic companion plant pairing, though it’s a little more one-sided than some of the others. Carrots will improve your tomatoes, and the carrots will have excellent flavor, except they tend to be quite a bit smaller than usual when planted near tomatoes. There isn’t a particular reason why these two behave this way, they just do.
What NOT to Plant Together
The companion premise works in reverse too. There are some plants that you should not plant near each other if you can avoid it. Sometimes it’s a chemistry conflict, and sometimes certain plants attract pests that are a problem for other plants.
Corn and Tomato
This is another pairing with a matched set of insect pests, so it’s best to keep them separated. Corn earworm and tomato hornworm are very similar both can be a serious problem to either plant.
Cucumbers and Potatoes
Keep these two vegetables apart because the cucumbers tend to attract a blight that effects potatoes. The cucumbers themselves don’t usually suffer too much, though they can produce smaller fruit if potatoes are near.
Beans and Beets
The nitrogen that makes beans so helpful for other crops is a problem if you grow them near root vegetables. The nitrogen makes a plant sprout leaves, not develop large roots. This is very evident with beets, so keep them away from your bean plants.
Peppers, Tomatoes and Potatoes
A 3-way set of problem plants. All of these vegetables are related, and are susceptible to certain blights. Keeping them all close together puts them all at risk from a disease disaster, especially if you don’t rotate your crops and the infections accumulate in the soil.
Trying to balance all these matches and pairings can be complicated, especially if you have a small space to garden in the first place. Don’t necessarily worry about taking advantage of using every single companion, or you can end up trying to play Tetris with your garden patch. Find a few suggestions that would be the most beneficial to you, and start off with those.
Take notes each growing season and see what kinds of results you get when you start trying out new pairings and placements. If you’re very curious, try experimenting with one patch using a companion arrangement, and another patch that is not. Does the kale near the mint have less insect damage than the kale planted on the other side of the yard? A year or two of observations can make a huge difference in seeing how well your companion choices are working for you.
None of these rules are set in stone, and often they are results of generations of observation from gardeners rather than actual scientific experiments. You may see certain ones work well for you while others don’t.
Whether you’re growing a handful of plants in your kitchen window or a whole yard of vegetables, knowing about companion planting can improve your gardening skills.