Radishes are one of my favorite crops to grow in the garden. They’re quick to mature, come in various colors, and are easy to tuck into empty spaces.
Plus, many people love them! Whether you pickle them for tacos, cut them in half and dip into ranch dressing, or put a few thin slices on buttered toast, their crisp texture and slightly spicy flavor brighten any dish.
Perhaps that’s why they fly off the shelves at the farmers’ market, no matter the time of year.
While radishes are generally easy to grow, pairing them with the right plants can make it easier to grow a successful crop. Join us as we cover some of the best companion plants for radishes as well as the benefits of using companion planting when growing radishes.
The Benefits of Companion Planting When Growing Radishes
Companion planting refers to the practice of growing plants together so at least one plant provides benefits to the other. Sometimes, the plants form a mutualistic relationship where both plants receive a benefit from the other.
Utilizing companion planting when growing radishes can provide various benefits to the radishes and/or the plant they are growing with. Here are some of the reasons why you should consider implementing companion planting when growing radishes.
Naturally Control Pest Populations
While radishes are quick-growing crops that are relatively carefree, they are susceptible to attack from various pests. Flea beetles, yellow margined leaf beetles, cabbage worms, harlequin bugs, aphids, and other pests are all common pests of radish greens.
While a few of these pests probably won’t seriously damage your radishes, larger pest populations can completely destroy the greens. That means keeping pest numbers low is a key part of maintaining a healthy radish crop.
You may think that spraying pesticides or picking off insects are effective ways to control pests. And I’m not here to tell you that these methods don’t work. However, there are other ways to keep pest populations in check.
One way is to encourage the presence of beneficial preparatory insects that feed on pests. These beneficial insects include green lacewings, ladybugs, parasitic wasps, and tachinid flies.
The thing about these beneficial insects is that oftentimes only the larvae feed on pests. The adults, on the other hand, often feed on flower pollen and/or nectar.
That means that planting a diverse array of flowering plants can help attract beneficial insects to your garden. When the adults flock to your garden to feed on flowers, they are more likely to lay their eggs near the pests you’re trying to knock down.
When the eggs hatch, the larvae will begin attacking the pests, which will lower pest populations. That means you are less likely to need to spray insecticides to keep pests off your radishes.
Maximize Garden Space
Since some varieties of radishes grow so quickly (as little as three weeks to maturity in the summer), they can fit into empty spaces that are present as slower-growing plants mature.
By the time radishes begin to crowd out other plants, they will be ready to harvest.
Tucking radishes into these empty areas can help you maximize garden space. Rather than harvesting one crop out of an area, you can harvest two!
Break Up Compacted Soils
Compacted soils are often associated with various issues. Water can have difficulties flowing through the ground, a lack of air space can make gas exchange difficult, and plant roots have a more difficult time expanding.
While you can loosen compacted soils with tools like a digging fork or broad fork, you can also rely on plants like radishes. As the plant’s long taproot grows through the soil, it helps break up compaction.
Many types of radishes can help reduce soil compaction, but some types are better than others. Larger tillage radishes and daikon radishes are some of the best varieties for breaking up extreme compaction.
While you can grow radishes alongside other crops, the best way to deal with compaction is to plant the radishes in the fall and let them grow throughout the winter. Come springtime, the soil will be loosened and ready for new crops.
Top Radish Companion Plants
If you are looking for plants to grow alongside your radishes, check out this list of some of the best radish companion plants.
1. Calendula
While radishes can benefit from having flowering plants around, it can be difficult to find flowers that bloom during cooler weather. And that can be a problem since radishes thrive in the spring and fall!
That’s why calendula makes a great companion plant. This plant produces lots of daisy-like flowers during cooler weather.
As long as you remove old calendula flowers, the plants will continue to flower for multiple months.
Calendula plants may begin to fade when hot weather arrives. However, many types of radishes will also become stressed if high heat is present.
2. Peas
One reason that peas and radishes are great companions is that they both thrive in cooler weather. Both plants can survive—and thrive—in cooler spring temperatures that many other crops cannot.
And since peas have a relatively long time to maturity (about 60 days), it makes sense to want to tuck another crop beside them. Smaller radishes will be ready to harvest in about 30 days, which allows you to pick them before the peas form dense shade.
I like to plant a row of radishes on either side of a row of peas. Trellising the peas keeps them off the radishes, and planting radishes can help shade out weeds and keep them away.
Peas also contain root nodules that contain nitrogen-fixing bacteria. These bacteria take gaseous nitrogen from the atmosphere and convert it into a plant-available form.
While the peas use some of this nitrogen, the unused portions are released back into the soil. Plants like radishes can then take up this nitrogen.
3. Nasturtium
Nasturtium plants produce edible leaves and flowers, both of which have a peppery taste that’s reminiscent of horseradish or mustard greens. However, it’s the flowers that benefit radishes.
Since nasturtiums flower over multiple weeks or even months, they provide a continuous supply of nectar and pollen. That means that they supply food to beneficial insects like green lacewings, parasitic wasps, and hoverflies.
When the adult forms of these insects are already present in your garden, they’re more likely to lay eggs on or near pests like aphids, flea beetles, and cabbage worms. When the eggs hatch, the larvae will feed on the pests and keep their populations in check.
Another reason why nasturtiums and radishes can be great companion plants is that they both thrive in cool weather. While many flowering plants don’t bloom until summer arrives, nasturtiums thrive in the cool spring.
Before you plant nasturtiums, be aware that there are two main types: climbing and bush.
Climbing varieties will trail throughout your garden and can be trained to grow up a trellis. Bush varieties stay more compact and don’t take well to trellises.
4. Onions
While onions are a wonderful garden crop, they take a bit of time to mature. No matter if you plant onion sets or seedlings, it will take a few months for the bulbs to be ready to harvest.
During the first few weeks of growth, onions are also quite small, about pencil thin. That means that when you’re growing rows of onions, you’re often left with lots of empty space in between the rows.
This empty space can be taken over by weeds, which means that you’ll need to stay on top of weeding. However, growing another crop in this empty area can help shade out weeds.
Radishes can be a great crop to tuck in between onion rows due to their quick-growing nature.
The radishes will be ready to harvest in about four weeks. After you remove them from the ground, the onions will have more room to mature.
If you want to grow radishes between rows of onions, it’s best to choose small varieties like French Breakfast and Cherriette. Stray away from larger and slower-maturing radishes.
5. Tomatoes
Tomatoes are another crop that is relatively slow to mature. Most varieties take between two and three months from the time you plant the seedlings in the ground until the time you pick your first tomato.
Rather than let the ground around your tomatoes sit idle as the plants mature, you can tuck some radishes beside your plants.
I like to plant a row of radishes on either side of my tomato plants, about eight inches away from the tomatoes. You can plant the radish seeds at the same time that you transplant the tomatoes.
You’ll likely end up harvesting the radishes when your tomato plants are about three to four feet tall. That means the radishes will be out of the way before the tomatoes become unruly.
6. Lettuce
Since radishes and lettuce both love cool weather, they’re natural companions.
These crops also work well together due to their complementary root systems.
Lettuce plants have shallow roots that take nutrients and water from near the top of the soil. However, radishes have a long taproot that can reach water and nutrients located deeper in the soil. Plus, this taproot can help break up compaction and improve soil structure.
Both baby lettuce mix and full lettuce heads make good companions for radishes.
7. Marigolds
Looking for another flowering plant to grow alongside your radishes? Check out marigolds!
These flowers come in a wide variety of hues and shapes which means you can find the perfect fit for your garden and style.
As long as you remove dying flowers, marigold plants will produce flowers through the summer and early fall. That means the plants are a continuous source of nectar and pollen for beneficial insects.
Marigold flowers can be a food source for adult insects including green lacewings, parasitic wasps, and hoverflies. The larvae of these beneficial insects can feed on radish pests including aphids, harlequin bugs, and flea beetles.
You may have also heard that the scent of marigolds can repel bad bugs. But is this true or is it just an old wives’ tale?
One research study reported that interplanting marigolds with other plants helped to decrease the number of aphids present. However, it’s unknown if this was due to the marigolds’ ability to “repel” aphids or its tendency to attract predatory insects that feed on aphids.
Another study reported that some types of marigolds release chemicals that can kill harmful nematodes.
So while marigolds may not repel all pests, they are known to keep some pests at bay.
8. Peppers
While peppers love the heat, high temperatures tend to stress radish plants. So why are these two good companions?
Well, peppers take a while to mature. That means you’ll need to tuck them in your garden in the late spring if you’re hoping for a mid-summer harvest.
I like to tuck some radishes beside pepper plants when the weather is still cool and the plants are still small. The quickly-growing radish roots help break up compacted soil and also help you maximize your garden space.
If you plant radish seeds at the same time you transplant your peppers, you can tuck the seeds in the ground about six inches away from the plants. By the time the pepper plants are beginning to crowd out your radishes, the root crops will be ready to harvest.
The Worst Radish Companion Plants
Radishes can grow well with just about any crop. They’re quick to mature, don’t overtake other crops, and can help with soil compaction.
Some people say that you should avoid growing radishes with other brassicas. That’s because crops like broccoli, cauliflower, and kale are susceptible to some of the same pests as radishes.
However, if you grow these crops together and pests appear, treating pests in one location rather than in two locations is easier. You can also cover all your brassica plants with insect netting to help keep pests away.
