General
Zucchini is a fast-growing summer squash (Cucurbita pepo) grown for frequent harvest of tender, immature fruits. Most garden types are compact bush forms; some are semi-vining. Choose varieties suited to your space: bush types for small beds and containers, semi-vining for larger plots. Parthenocarpic cultivars are useful in cool or rainy periods with poor pollinator activity and for protected cultivation. The plant thrives in warmth and rich soil, and is highly productive when watered and fed consistently.
Light
Full sun (6–8+ hours).
Soil type
Deep, fertile, well-drained yet moisture-retentive loam enriched with compost or well-rotted manure.
Water requirement
High; keep soil evenly moist, not waterlogged.
Nutrient requirement
High feeder; steady supply of nitrogen early, then balanced feeding through fruiting.
Precultivation
Sow 1 seed per 8–10 cm pot, 2–3 cm deep, in mid-April to mid-May. Optimal germination 22–25°C; emergence in about a week. Grow on at 18–22°C in strong light. Do not overwater. Pot up to 12–13 cm if roots fill the pot. Harden off for 7–10 days once nights are consistently above 8–10°C. Aim for sturdy transplants with 2–3 true leaves; avoid root disturbance when planting out.
Planting
Plant out after frost when daytime >15°C and nights >8–10°C; soil ideally >12°C. Space 90–100 cm between plants (120–150 cm for vigorous types). Plant on a low mound or ridge to improve drainage and warmth. Work in 3–5 L of mature compost per plant plus a balanced organic fertilizer at planting. Mulch (straw/grass clippings/leaf mold) after soil has warmed to conserve moisture and reduce splash. In windy or cool sites, use row cover or fleece early in the season and remove during flowering unless using parthenocarpic cultivars.
Pruning
Routine pruning is minimal. Remove a few oldest, yellowing leaves and any that touch the soil to improve airflow and reduce disease from mid-summer onward. On semi-vining types, you can tip the growing point late in the season to concentrate energy on ripening existing fruit. Thin excess small fruits if plants are overloaded or during cool spells.
Maintenance
Water deeply 2–3 times per week in dry weather (25–30 mm/week) to maintain even moisture and prevent blossom end rot. Avoid wetting foliage late in the day. Feed at planting, then side-dress with compost or a balanced organic fertilizer every 3–4 weeks from mid-June through August. Liquid feeds (compost tea/comfrey/nettle) can supplement during heavy fruiting. Keep beds mulched and weed-free. Rotate beds and remove crop residues promptly at season end.
Harvest
Pick young and often for best flavor and continuous production: 15–20 cm long for cylindrical zucchini, 5–8 cm across for pattypan. Harvest 3–5 times per week in peak season. Use pruners to avoid tearing stems. Male blossoms are edible; harvest in the morning, leaving enough for pollination. Store unwashed at 7–10°C for 3–5 days; avoid colder storage which causes chilling injury. Oversized fruits reduce further yield—remove promptly. Peak picking is in mid-summer; as nights cool in early autumn, harvest smaller fruits more frequently to avoid chilling injury. Cease harvest ahead of frost.
Common issues
Cold stress and frost cause plant collapse—protect early plantings. Irregular watering leads to blossom end rot and misshapen fruit; maintain even moisture. Poor fruit set arises from cool, rainy weather or low pollinator activity; hand-pollinate or grow parthenocarpic varieties. Powdery mildew appears late season—improve airflow, avoid excess nitrogen, water soil not leaves, and remove affected leaves; sulfur or bicarbonate sprays can help organically. Slugs/snails damage seedlings—use barriers, hand-picking, traps. Viral diseases (mosaic) show mottled leaves and distorted fruit—remove plants and control aphids; observe 3–4 year cucurbit rotation.
Rotation schedule
Rotate cucurbits on a 3–4 year cycle. Follow heavy-feeding squash after legumes or well-manured beds, then plant light feeders or alliums the next year. Avoid growing after or next to cucumbers, pumpkins, or melons to reduce shared pest/disease pressure.
Pollination
Monoecious, insect-pollinated; parthenocarpic cultivars can set fruit without pollination.
Companion plants
Sweet corn, pole beans, nasturtium, marigold, calendula, borage, dill, onions/garlic at bed edges.
Incompatible plants
Fennel; avoid planting with or after other cucurbits (cucumber, pumpkin) due to shared pests/diseases; keep distance from potatoes.
