Everyone knows the joke about finding a bulbous zucchini on the doorstep left behind by a generous neighbor who has planted too much and resorts to giving these veggies away. An overabundance of zucchinis may be a curse that befalls many gardeners, the opposite is sometimes true in the case of cucumbers. A garden-fresh cucumber is a welcome addition to summer salads, but cucumber plants can be prone to bacteria and mildew. That's why planting them with beneficial companion plants can help keep nasty insects at bay and attract beneficial bugs instead.
Companion planting is a method of sowing vegetable and herb seeds in a garden so that plants "support" each other by repelling insects or infusing the soil with nutrients. Planting companion veggies together helps you increase the overall density of what you can grow in a small plot, plus you'll yield a more productive crop. Cucumbers and zucchinis are from the same family -- Cucurbitaceae, or the squash family -- so these cousins can be planted together in your vegetable garden.
Before you decide to toss a handful of cucumber and zucchini seeds in the soil, make sure you create optimum growing conditions for each. Cucumbers thrive in well-drained soil, plus they need full sun and plenty of room to grow. Once threat of frost has passed, cucumber seeds can go into the ground in early spring. Zucchinis also like full sun, but wait until the soil is at least 75 degrees Fahrenheit, otherwise seeds may not spout. Planting dates will vary depending on what U.S. Department of Agriculture hardiness zone your garden is in.
In "Great Garden Companions," master gardener Sally Jean Cunningham suggests sowing four cucumber seeds one foot apart in a mound or hill. You could simply sow the seeds into the soil, but creating a mound ensures the soil warms up quicker, which means you can get seeds into the ground earlier in the season. Sow zucchini seeds in a row 12 to 16 inches apart right down the middle of the square mound where you've planted your cucumbers. This way each plant has ample room to grow.
Once your cucumbers and zucchinis are nested in their garden beds, add some other beneficial companion plants such as basil, which repels flies and mosquitoes, and oregano, which repels cucumber beetles. Tuck some radishes in among the rows -- they help keep squash borers away from your zucchinis. Avoid planting sage and potatoes next to cucumbers and zucchinis.