What to Plant With Radishes: Radish Companion Plants (and the Carrot Debate)

Radishes are the fastest crop in most vegetable gardens. They sprout within days, are ready to pull in a few weeks, and take very little room, which makes them easy to tuck between slower crops. The catch is that they want cool weather and steady moisture; in heat or dry soil they turn woody, hot or go to seed. This guide covers what extension sources list as radish companions, the carrot debate, and how to time and grow radishes so they stay crisp.

Good companion plants for radishes

Lettuce and peas

Lettuce, peas and radishes all go in early, a few weeks before the last spring frost, so they fit naturally in one cool-season bed. Radishes come out first, leaving room for the lettuce to fill in and the peas to climb. See what to plant with lettuce and what to plant with peas.

Cucumbers

Virginia Extension lists radishes as a cucumber companion. Cucumbers are sown after the last frost, so the overlap is short: a late-spring sowing of radishes around young cucumber plants is harvested before the vines spread. More in what to plant with cucumbers.

Nasturtiums

Nasturtiums are a listed radish companion. They are an easy, edible flower for the bed edge and bring color while the vegetables grow. See nasturtium companion plants.

Radishes and carrots: sources disagree

The traditional trick is to mix a few radish seeds into a row of slow-sprouting carrots. The radishes come up quickly and mark the row, and pulling them early loosens the soil as the carrots get going. The risk is crowding: if radishes are sown thickly or left too long, they compete with the young carrots. If you try it, sow radishes sparingly and pull every one on time. Our carrot guide covers both sides.

What not to plant with radishes

None of the extension sources we use list a vegetable as incompatible with radishes, so we do not show a keep-apart table here. A few practical cautions still apply:

• Shade and crowding. Radishes planted too close together, or under the shade of tall crops, make leaves but no usable roots. UMN Extension notes that radishes planted too close do not develop.
• Cabbage-family rotation. Radishes belong to the cabbage family and share some of its pests and diseases, such as flea beetles, cabbage maggots and clubroot. When you rotate beds, group radishes with cabbage, broccoli and kale. See what to plant with broccoli.
• Summer heat. In hot weather radishes bolt, turn woody or taste very hot, so do not plan them as a midsummer neighbor for warm-season crops.

For pairs that sources do list as incompatible, see the keep-apart chart.

When to plant radishes

Radishes are cold tolerant and do best in cool weather. Direct sow them in spring from about four weeks before your last frost up to the frost date, and again in late summer for a fall crop (UMN Extension suggests August through early September in Minnesota). Sow small batches every two to three weeks rather than one big row, so you have a steady supply instead of a glut that turns pithy. Our planting calendar shows the spring window for your frost date. More crops and intervals are in our succession planting guide. Carrots, often sown alongside radishes, have their own schedule in when to plant carrots. Radishes, beets and turnips share a schedule; see when to plant beets for all three.

Planting and spacing

• Soil: loose and well drained, with a pH of about 6 to 7. UMN Extension suggests loosening the soil at least six inches deep, and a foot or more for long types such as daikon.
• Depth: about ¼ to ½ inch deep for small garden radishes, up to an inch for larger types.
• Spacing: sow about an inch apart, then thin to about two inches between plants. Daikons need four to six inches.
• Fertilizer: compost worked in ahead of time is usually enough. Avoid fresh manure, which UMN Extension notes can make roots branch.
• Emergence: seedlings usually appear within ten days. If rain leaves a crust on the soil, a light sprinkle helps them push through.

Water and common problems

Radishes grow best when they grow fast and without stress. UMN Extension recommends about an inch of water a week, more often on sandy soil, because drought stress gives roots poor flavor and a tough texture, and uneven moisture can make them crack. Other common issues:

• All leaves, no root: usually crowding or too much shade. Thin early.
• Hot, woody or hollow roots: slow growth, heat, or roots left in the ground too long.
• Small holes in the leaves: flea beetles, most common on young spring plants. A row cover over new sowings helps.
• Tunnels in the roots: cabbage maggots or wireworms.

A simple cool-season bed with radishes

1. Peas on a trellis along the north side.

   A listed radish companion, sown about four weeks before the last frost.

2. Lettuce in the middle.

   Another listed companion that likes the same cool weather.

3. Radishes in the gaps and along the front edge.

   Sown every two to three weeks and pulled in three to five weeks.

4. Nasturtiums at the corners.

   Planted after frost, once the early radishes are out.

This is close to the cool-season bed in our raised bed layouts. Keep onions and garlic out of this bed, since sources list them as incompatible with both peas and lettuce.

Harvest

Garden radishes are usually ready three to five weeks after sowing. Pull them as soon as they reach a usable size; left in the ground, they become fibrous and strong tasting. Remove the greens and wash the roots. UMN Extension notes that garden radishes and daikon keep only a week or two in the refrigerator before they shrivel.

Radishes in containers

Small round radishes are one of the easiest crops for a pot or window box. Use a container at least six inches deep with drainage holes, keep it in sun, and water often, since small containers dry out quickly and dry soil makes radishes hot and tough.

Frequently asked questions

What grows well with radishes?

Extension-listed companions for radishes in our checker are cucumbers, lettuce, nasturtiums and peas. The table on this page explains why each pairing works.

What should you not plant with radishes?

Our sources do not list any plants as incompatible with radishes. Sources disagree on carrots.