Summer Squash - Key Growing Information

Several varieties of summer squash being harvested from the field for evaluation by our breeding team.


SCIENTIFIC NAME: Cucurbita pepo
CULTURE: Fertile, well-drained soil with a pH of 5.8–6.8 is best. Plastic mulch and fabric row covers (AG-19 grade) can aide plant establishment and exclude insect pests during the seedling stage. Row covers should be removed when plants begin to flower. Poor fruit development may indicate insufficient pollination. For highest quality fruit, succession plantings every 2-3 weeks may be needed.
PLANT SPACING: Space plants 18-24" apart in rows 6' apart. Wider spacing may allow for easier harvesting.
DISEASES AND PESTS: Common cucurbit diseases include powdery mildew, downy mildew, bacterial wilt, and phytophthora. Avoid problems with adequate soil drainage, good air flow, insect pest control, and crop rotation. If necessary, check with your local Cooperative Extension Service agent for specific control options.
HARVEST FRUIT: For some varieties, it is common for the first fruits to be malformed, wither, or blacken, which indicates poor pollination and is usually remedied as more male flowers appear. Harvest regularly, 2-3 times a week, once plants begin to produce. Cut or gently twist off fruits when they have reached the desired size. For zucchini, 6-8" long; summer squash, 4-6"; and patty pan and round, 2-3" in diameter. Handle with care to avoid scratching fruits.
HARVEST BLOSSOMS: Harvest male blossoms (with thin stems) or female blossoms (with thick stems and an immature fruit at the base of the flower) in mid to late morning when fully open. Clip flowers 1-2" below flower base. If a squash fruit crop is also desired from the same planting, only harvest male flowers, leaving a few to pollinate the female flowers.
STORAGE: Keep fruit at 40-50°F (5-10°C), 95% relative humidity for up to 2 weeks. Use as soon as possible for best quality.
DAYS TO MATURITY: From direct seeding; for days to maturity from transplanting, subtract about 14 days.
AVG. DIRECT SEEDING RATE: (at 3 seeds/ft., rows 6' apart) 250 seeds/83', 500 seeds/166', 1,000 seeds/333'.
SEED SPECS: SEEDS/LB.: Zucchini: Avg. 3,400; Yellow Summer: Avg. 5,500; Specialty: Avg. 4,500.
PACKET: 30 seeds (unless otherwise noted), sows 10'.