Start indoors or direct sow?

Direct sow zucchini because it dislikes root disturbance and quickly catches up when planted in warm soil. An indoor start is possible for a slight head start, but keep it brief and transplant carefully.

When to start Zucchini seeds

Direct sow 1 to 2 weeks after your average last spring frost, when soil is at least about 65°F. If starting indoors, sow 3 to 4 weeks before the planned outdoor planting date.

How to sow the seeds

Sow seeds 1 inch deep in rich, well-drained garden soil for direct sowing. For indoor starts, sow one seed in a 3 to 4 inch biodegradable pot of seed-starting mix so roots can stay undisturbed.

Germination

Zucchini usually germinates in 4 to 10 days. Warm soil, roughly 70 to 95°F, and even moisture support fast, uniform emergence.

Seedling care

Indoor seedlings need strong light and moderate watering, with the potting mix allowed to dry slightly on top between waterings. Thin direct-sown plants to final spacing, and provide clean containers, airflow, and careful watering to prevent damping off.

Transplanting & hardening off

Direct-sown zucchini needs no transplanting. Harden indoor seedlings off for about a week and set them out after frost only while they are small and not root-bound.

Tips

Plant a few seeds at a time at staggered dates rather than sowing all your zucchini at once. Protect young plants from cold nights with a row cover or cloche, then remove covers when flowering begins.

General seed-starting guidance for US home gardens; timing depends on your local frost dates and variety. Page updated Aug 4, 2026.