Growing Squash

Summer squash picks: Zucchini (Dark Star, Costata Romanesco for farmers markets), Yellow Crookneck (classic, prolific), Pattypan (unique shape, premium market item), Cousa (Middle Eastern type, excellent stuffing squash). Summer types produce within 45-55 days and are harvested continuously.

Winter squash picks: Butternut (Waltham, Honeynut for premium sales - the best storage and flavor combination), Acorn (Table Queen, compact vines), Delicata (sweet potato flavor, edible skin, premium pricing), Kabocha (dense, sweet flesh, popular in Asian cuisine), Spaghetti Squash (novelty appeal), Hubbard (huge, excellent storage). Winter types need 80-110 days and are harvested once at maturity.

Squash germinate quickly in warm soil (70-95°F) and dislike transplant shock. Direct sowing after the last frost when soil is warm is the simplest approach. Plant 1 inch deep. For summer squash: space 24-36 inches apart in rows 4-6 feet apart. For winter squash vines: space 36-48 inches apart in rows 6-10 feet apart, or plant on hills (mounds) with 2-3 plants per hill, hills spaced 6-8 feet apart.

For an early start in short-season climates, start indoors 3-4 weeks before last frost in large pots (4 inch) - squash seedlings grow fast and become rootbound quickly. Transplant carefully without disturbing roots. Use biodegradable pots that can be planted directly. In tropical climates, squash grows year-round; plant in succession every 4-6 weeks for continuous production.

Squash have separate male and female flowers on the same plant (monoecious). Male flowers appear first on thin stems; female flowers follow 1-2 weeks later and have a small fruit (ovary) at the base. Bees must transfer pollen from male to female flowers for fruit to develop. Each female flower is open for only one day - if it is not pollinated, the tiny fruit yellows and drops.

If you notice fruit starting to form but then rotting and falling off, poor pollination is likely the cause. Solutions: plant flowers nearby to attract bees, avoid pesticides during morning hours when bees are active, and hand-pollinate if necessary (use a small brush to transfer pollen from a male flower's anthers to the female flower's stigma early in the morning). A single male flower can pollinate 2-3 female flowers.

Squash are heavy feeders and drinkers. Provide 1-2 inches of water per week through drip irrigation or soaker hoses - avoid overhead watering, which promotes powdery mildew. Water at the base of the plant in the morning. Mulch heavily (3-4 inches of straw or leaves) to retain moisture and prevent fruit rot from soil contact.

Side-dress with compost or balanced fertilizer when vines begin to run. Winter squash are especially hungry for potassium during fruit development - apply wood ash or sulfate of potash around each hill. For vine management, you can train winter squash vines in a specific direction to stay within their allotted space, or grow compact bush varieties (Bush Delicata, Butterbush) if space is limited.

Summer squash: Harvest small and often - zucchini at 6-8 inches, pattypan at 3-4 inches diameter. Check plants every 1-2 days; a zucchini can grow from 6 inches to 18 inches in 48 hours in warm weather. Oversized summer squash become seedy and watery. Regular harvesting signals the plant to keep producing new flowers and fruit.

Winter squash: Leave on the vine until the skin is hard (fingernail test - your nail should not easily puncture the skin), the stem is dry and corky, and the ground spot (where the fruit rested on the soil) has turned from white to cream or yellow. Cut the stem with pruning shears, leaving 2-3 inches of stem attached - pulling the stem off creates an entry point for rot. Cure winter squash in a warm (80°F), dry place for 10-14 days to harden the skin before storing in a cool (50-55°F), dry location.

For continuous summer squash production, succession plant every 3-4 weeks from last frost through midsummer. Each planting produces for 4-6 weeks before powdery mildew or vine borers reduce productivity. Having a fresh planting coming into production as the older one declines ensures an unbroken supply for market or kitchen.

In the Three Sisters system, winter squash (or pumpkins) are planted between mounds of corn and beans. The squash vines spread along the ground, shading the soil to suppress weeds and retain moisture. Their spiny leaves and stems also deter raccoons and other animals from the corn. Use vining winter squash types (butternut, hubbard) for Three Sisters - bush types do not spread enough for effective ground coverage.