What to Plant With Corn: Corn Companion Plants (and What to Avoid)

Corn is the tallest thing most people grow in a vegetable garden, and that shapes everything about where it goes. It casts a lot of shade, it needs to be planted in a block rather than a single row so it pollinates well, and it gives climbing crops something to grow up. The best corn companions take advantage of that height and that block shape. Here is what extension sources list, and how to plan around it.

Good companion plants for corn

Beans and squash: the Three Sisters

Maryland, Oregon State and Virginia Extension all describe corn and beans as companions: pole beans twine up the corn stalks, and their roots sit at a different depth. Squash, spread around the base, shades the soil and helps hold down weeds. Give the corn a head start of a few weeks so the stalks are sturdy before the beans start climbing. See what to plant with beans and what to plant with zucchini for the other two sisters. Our step-by-step Three Sisters garden guide covers mounds, varieties and timing.

Cucumbers

Oregon State and Virginia Extension list cucumbers as corn companions, since sturdy corn stalks can support small, vining cucumber varieties. Plant the cucumbers once the corn is established, and pick compact varieties so the vines do not pull stalks over. More in what to plant with cucumbers.

Peas and potatoes

Both are listed corn companions in Virginia Extension guidance. Peas are a cool-season crop sown weeks before corn, so they can use the edge of the corn bed early in the season. Potatoes go in a row on the sunny side of the corn block so the tall stalks do not shade them. See what to plant with potatoes.

What not to plant with corn

Tomatoes are the crop Virginia Extension lists as incompatible with corn. Both are big, hungry summer crops, and a corn block will easily shade a tomato row. Plant them in separate beds, or at least keep the tomatoes well away from the corn's shadow. Our tomato guide covers better tomato neighbors, and every pair to separate is in the keep-apart chart.

Plant corn in a block, not a row

Corn is pollinated by wind: pollen falls from the tassels at the top of the plant onto the silks of the ears. UMN Extension recommends planting in blocks of at least four rows. In a single long row, much of the pollen blows away, and the ears end up with blank patches where kernels did not form.

A block also matters for neighbors. Put the corn on the north side of the garden, where its shade falls outside the bed rather than over shorter crops. University of Maryland Extension even suggests using that shade on purpose, planting later lettuce where sweet corn shades it in the hottest part of the day (see what to plant with lettuce).

Planting and spacing

• Wait for warm soil: UMN Extension says corn seed germinates best when the soil is close to 60°F; supersweet types and untreated seed want closer to 65°F. A soil thermometer takes the guesswork out.
• Depth: about one inch deep. Small supersweet seeds should go no deeper than three-quarters to one inch, and the seedbed needs to stay moist until they emerge.
• Spacing: 8 to 12 inches apart in rows 30 to 36 inches apart, in a block of at least four rows.
• Soil: well-drained soil with organic matter and a pH of 5.8 to 7.0, fertilized according to a soil test.

A simple Three Sisters block

1. Corn in a block on the north side.

   At least four short rows, 8 to 12 inches apart in the row.

2. Pole beans at the base of the corn.

   Sown once the corn is several inches tall, so the stalks can carry them.

3. Squash or zucchini around the edges.

   Its big leaves shade the soil; give it room to spread outward.

4. Potatoes or a cucumber row on the sunny side.

   Both are listed corn companions.

Keep tomatoes in a different bed. Our raised bed layouts include a ready-made 4×4 Three Sisters plan.

When to plant corn

Corn is a warm-season crop sown directly in the garden from about your last frost date, once the soil has warmed. UMN Extension notes that planting early and choosing varieties that mature in under 80 days can help you avoid the corn earworm and European corn borer, two caterpillars that feed on the ears. Our planting calendar turns your frost date into a sowing window.

Watering, harvest and pests

Aim for about an inch of water a week, more often in sandy soil. UMN Extension points out that corn keeps growing in very hot weather but can become drought-stressed in dry spells, and its roots are fairly shallow, so steady watering matters. Hoe shallowly to control weeds until the plants form a canopy.

Harvest when the kernels in the middle of the ear are full and give a milky liquid when squeezed, usually 18 to 24 days after the silks first appear, when the silks are drying and browning. Watch for birds pulling up seed (a floating row cover until emergence helps) and raccoons at harvest time.

Corn in small gardens and containers

Corn is not a natural container crop, because it needs that block of plants to pollinate. In a small space, a raised bed planted as a tight 4×4 block is about the minimum for decent ears; treat it as a fun, small harvest rather than a big one.

Frequently asked questions

What grows well with corn?

Extension-listed companions for corn in our checker are beans, cucumbers, peas, potatoes, pumpkins and squash (including zucchini). The table on this page explains why each pairing works.

What should you not plant with corn?

Our sources list tomatoes as a poor neighbor for corn.