How to Raise Summer Squash in Zone 5

Plant summer squash seeds directly in the garden after the last frost date has passed and the soil warms to at least 70 degrees Fahrenheit. Use a soil thermometer, available in most garden centers, to determine soil temperature. Don't plant too early because seeds planted in cold soil may rot before they germinate.

Spade or till the soil to a depth of at least 12 inches. Dig in up to 4 inches of compost or organic material, along with 4 to 6 cups of a dry, 10-10-10 fertilizer for every 100 square feet of planting space.

Make shallow furrows with a hoe, allowing 2 to 3 feet between each furrow. Plant the seeds 2 inches apart and cover them with 1/2 inch of soil.

Water immediately and keep the soil lightly moist until the seeds germinate. Thereafter, provide 1 inch of water whenever the top 4 inches of soil is dry -- usually about once per week in warm weather. Water deeply, providing at least 1 inch of water each time.

Protect seedlings from cool air by covering them with hot caps or other row covers. Remove the covers as soon as temperatures reach 90 degrees Fahrenheit or when the plants begin to flower.

Thin the squash plants to a distance of 8 to 12 inches when the seedlings have two leaves.

Spread 2 to 3 inches of mulch around the squash plants when the seedlings are about 2 inches tall and the soil is at least 75 degrees F., as mulch conserves moisture and keeps the roots evenly warm. Use a loose mulch such as straw, dry grass clippings or chopped leaves.

Side-dress the squash with a high-nitrogen, 21-0-0 fertilizer when the plants develop runners. To side-dress, sprinkle the fertilizer along the rows about 6 inches from the plants, using 1 to 2 tablespoons of dry fertilizer per plant.

Control weeds regularly, either by scraping the surface of the soil with a hoe or by hand-pulling. Weeds compete with the plants for soil nutrients and moisture. Also, weeds and other plant debris often promote mildew and other diseases caused by humid conditions or poor air circulation.

Harvest summer squash when the squash is small and tender and the skin is soft enough to scratch with your fingernail. Don't allow overripe squash to remain on the vine, as regular harvest promotes continued production of squash.