What to Plant With Zucchini and Squash: Companion Plants (and What to Avoid)

Zucchini and other summer squash are generous plants, sometimes too generous. Their big leaves shade everything around them, so choosing companions is as much about space and timing as about which plants "like" each other. Here is what extension sources list as good and poor squash neighbors, plus a few layouts that work.

Good companion plants for zucchini and squash

Corn and beans: the Three Sisters

Squash is one of the Three Sisters with corn and beans. Corn grows tall, pole beans climb the corn, and squash spreads below, shading the soil and smothering weeds. Traditionally the "sister" was a vining winter squash or pumpkin. A bush zucchini works in a small planting, but it forms a clump rather than a carpet of vines, so plan on hand-weeding a little more.

Nasturtiums and marigolds

Virginia Extension lists both flowers as squash companions. They are easy to grow from seed, cheerful along the bed edge, and draw pollinators and beneficial insects. Nasturtiums are often described as a "trap crop" that lures pests away from squash. The evidence for that in home gardens is thin, so plant them for the flowers and the bees, and treat any pest benefit as a bonus.

Bush beans

Outside a Three Sisters planting, bush beans are still a good match. They stay low, fix some nitrogen over time and fill gaps while the zucchini is small. Plant them where the squash leaves will not swallow them by midsummer.

What not to plant with zucchini

Potatoes are the listed conflict. Like cucumbers, squash vines and big leaves crowd potatoes, which need room to be hilled during the season and dug at the end. Give potatoes a bed of their own. The rest of the pairs to separate are in our keep-apart chart.

Zucchini with tomatoes, cucumbers and other crops

• Cucumbers are in the same family (cucurbits). They are not listed as bad companions, but they share cucumber beetles, squash bugs and powdery mildew, so leave space for airflow and rotate both to a new bed each year. See what to plant with cucumbers.
• Tomatoes and peppers have no listed interaction with squash. The real issue is size: a zucchini planted beside a young tomato can shade it out. Plant squash on the south or east edge, or in its own bed.
• Herbs and onions have no listed interaction either. Low herbs work at the bed edge, as long as the squash leaves do not cover them.

Give zucchini room

The most common zucchini mistake is crowding. An unstaked bush zucchini commonly spreads 3–4 feet across. Clemson Extension's square-foot chart fits one summer squash per square foot only when it is staked and grown upright; vining squash, pumpkins and melons need several squares each unless trellised. Crowded squash stays damp and shaded, which is where powdery mildew starts.

1. One or two plants is usually plenty.

   A single healthy zucchini can produce more than a small household eats.

2. Stake it upright.

   Tie the main stem to a sturdy stake as it grows and remove lower leaves that touch the ground. This frees space and improves airflow.

3. Put it on the edge.

   A bed corner or the south edge lets the leaves spill into the path instead of over neighbors.

Squash pests companions will not fix

Squash vine borers are the caterpillars of a day-flying moth that lays eggs at the base of the stem. Larvae tunnel inside, and a healthy-looking plant suddenly wilts. University of Minnesota Extension suggests covering young plants with row cover until they flower, and checking stems for holes and sawdust-like frass.

Squash bugs suck sap from leaves and stems. Check the undersides of leaves for clusters of bronze eggs and crush them, and hand-pick adults and nymphs early in the season, when numbers are small.

Two layouts that work

Three Sisters block

For a small planting, use our 4×4 Three Sisters plan in the raised bed layouts guide: corn in a block on the north side, pole beans sown once the corn is up, and squash spilling over the south edge.

Squash corner with flowers

In a 4×8 bed, give one staked zucchini a corner, plant bush beans in the squares beside it, and edge the bed with nasturtiums and marigolds. Keep potatoes elsewhere, and put cucumbers on a trellis at the opposite end if you want both.

When to plant zucchini

Zucchini is frost-tender and grows best in warm soil. Sow seeds outdoors at or shortly after your last spring frost, or set out young transplants carefully, since squash dislikes root disturbance. Our planting calendar turns your frost date into a sowing window. A second sowing a few weeks later can replace plants lost to borers.

Zucchini in containers

Pick a compact bush variety and the biggest pot you have room for, at least about 5 gallons and larger if possible. Grow companions such as nasturtiums in a separate pot or around the rim of a very large container, and water deeply and often: big leaves lose water fast on hot days.