Summer Squash (Cucurbita pepo)
Summer squash are harvested immature with soft skin and short shelf life. They are grown in both spring and fall in some climates. Varieties include:
- Straightneck: Yellow, bottle-shaped, straight neck.
- Crookneck: Yellow, bottle-shaped, curved neck, more difficult to harvest.
- Scallop: Flattened and ridged; white, green, or striped.
- Zucchini & Cocozelle: Green and yellow types; zucchini is the most common.
Commercial production favors straightneck and zucchini due to easier handling.
Temperature
Squash is a warm-season crop. Plant after frost. Germination is best at 85°F and poor below 60°F. For earlier harvests, use plastic mulch, row covers, proper orientation, or transplanting.
Soil
Best in sandy loam with high organic matter and pH 6.0–6.5. Use lighter soils for early crops. Avoid poorly drained fields. Rotate with non-cucurbit crops every 3 years to avoid soil-borne disease buildup.
Planting
Sow seeds 1–1.5" deep in rows 36–48" apart. Thin to 18–28" spacing. Use 3 lbs/acre (dribble) or 1 lb/acre (precision seeder). For plastic mulch, double rows spaced 18" apart are common. Plant every 10–14 days for a longer season, up to 60–70 days before frost.
Spacing
12–36" in row, 48–72" between rows
Harvest
Harvest when fruits are glossy and tender. Frequency depends on conditions—every 1–2 days is common. Leave a short stem on fruit. Use gloves to avoid skin damage. Quality declines as skin dulls. Harvest a planting for 2–3 weeks then move to the next.
Harvest standards by type:
- Crookneck & Straightneck: 1¼–2" diameter
- Zucchini: 6–8" long
- Scallop: 3–4" diameter
- Patty pan / Round: 2–3" diameter
Malformed first fruit is common due to poor pollination but resolves with more male flowers. Harvest consistently 2–3 times per week for best results.
Harvesting Blossoms: Harvest in mid to late morning when fully open. Cut 1–2" below flower base. Harvest only male flowers if fruit is desired from same planting.
For more information, please see links below:
- University of Kentucky - Summer Squash
- University of Arkansas - Squash Guide
- University of Minnesota - Growing Summer Squash
Note: This information is summarized. Additional details and expanded guidelines can be found in our production sheets available in the Holmes Seed Grower's Guidebook.
Downloadable Copy: