Start indoors or direct sow?

Direct sow winter squash because it develops quickly in warm soil and resents root disturbance. In shorter-season areas, start seeds indoors briefly in biodegradable pots and transplant young plants carefully.

When to start Winter Squash seeds

Direct sow 1 to 2 weeks after the average last spring frost, when soil is at least about 65°F. For indoor starts, sow 3 to 4 weeks before the outdoor planting date, after the threat of frost will be over.

How to sow the seeds

Plant seeds 1 inch deep in fertile, well-drained garden soil, often in mounds or rows with ample space for vines. For indoor starts, use one seed per 3 to 4 inch biodegradable pot with seed-starting mix, then avoid root disturbance.

Germination

Winter squash usually germinates in 5 to 10 days. Soil temperatures around 70 to 95°F and steady, moderate moisture encourage good emergence.

Seedling care

Keep indoor plants under strong light and water when the top of the mix begins to dry. Thin direct-sown seedlings to the intended spacing, and prevent damping off indoors with clean containers, airflow, and no standing water.

Transplanting & hardening off

Direct-sown winter squash needs no transplanting. Harden indoor seedlings off over about a week, then plant them at the same depth while they are young and before roots fill the pot.

Tips

Choose a variety whose days to maturity fit your local frost-free season. Warm the planting area with black plastic or a fabric cover if spring soil remains cool.

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