Summer Squash Growing Tips

Summer squash plants are heavy producers that need plenty of fertilizer and water to produce healthy foliage, flowers, and fruit. Fertilize them regularly with organic slow-release granules, manure, compost, or worm castings.

Squash plants grow best in full sun and well-drained soil, but can also tolerate partial shade or a few afternoon hours of shade. Water them deeply during dry periods.

Planting

Summer squash is a warm-season vegetable that can be sown in the spring. Planting is best after the last frost date and the soil temperature has warmed to 62 degrees F or higher.

Squash seeds do not germinate well in cold soil. They will sprout quickly when the temperatures are warm and the air is cool enough to protect them from frost.

To grow summer squash, choose a planting site with good drainage and a moist, but not soggy, soil. It is also important to incorporate some compost or aged manure into the soil before planting.

Sow seeds 1 inch deep, in rows or hills. Sow two or three seeds in each hill, spaced about 24 inches apart. When plants are 4 to 6 inches tall, thin them to the strongest seedlings in each group.

Watering

Summer squash plants need water regularly. They need at least an inch of water a week, whether by rain or irrigation. When it’s warm, they need even more.

Squash likes well-drained soil with a pH between 6.0 and 6.5. Mix in aged manure or compost to amend the soil.

A thick layer of organic mulch keeps the ground moist and discourages weeds from germinating. It also helps prevent diseases from affecting foliage and fruits.

Powdery mildew and downy mildew are common fungal diseases that affect summer squash leaves. If these infections are present, spray leaves with a solution of 2 tablespoons of neem oil concentrate to 1 gallon of water.

In addition to preventing these problems, a deep, consistent watering schedule will ensure healthy, productive plants. Use a drip system or soaker hose that waters at the base of the plant. A good layer of mulch will help your squash stay healthy and thriving, too.

Pruning

Summer squash vines can become very long and unwieldy. Pruning them back at the right time can help tame them and produce more fruit without diminishing their flavor.

As soon as four or five fruits are set on the vine, prune it off just enough to allow the plant to put its energy into growing new fruit. This will allow the fruits to develop faster.

The best varieties of summer squash include zucchini (green and yellow), yellow crookneck, pattypan or scalloped type (also called scallopini) and the long-necked Italian climber Trombetta di Albenga.

Whether you grow your squash in the ground or on a trellis, pruning is essential. It encourages the plants to focus on fruit production rather than foliage, and it can protect the main vine from disease spread.

Pruning can also reduce the chances that summer squash plants will contract powdery mildew, which is a common problem. This fungal disease is often caused by spores in the soil, but it can be prevented by regularly pruning and removing leaves that overlap or cross over from one plant to another.

Harvesting

Whether you’re growing zucchini, yellow squash (straightneck), or crookneck squash, it is very important to harvest them when they are at their best. Left too long, summer squash becomes bitter and mealy.

They also may become large and seedy, a sign that the plant is losing its ability to produce new fruit. It’s best to pick them when the skin is firm but tender and you can’t pierce it with your fingernail.

The fruit should be four to seven inches in length and two to three inches in diameter. It is also a good idea to hollow out slightly larger fruits and use them as stuffing or grated for baking purposes.

Summer squash are a great source of protein and fiber, as well as calcium and vitamin A. You can eat them raw or cook them, or they can be added to soups and stews for flavor and color. They are easy to grow and keep in the garden.