Start indoors or direct sow?

Start cauliflower indoors and transplant it while seedlings are young and actively growing. Direct sowing can work where seasons are long and mild, but it offers less control over timing and plant quality.

When to start Cauliflower seeds

For spring planting, start seeds indoors 4 to 6 weeks before the average last spring frost, then transplant around the last frost date or slightly earlier under protection. For fall crops, start seeds 5 to 7 weeks before transplanting in late summer, allowing heads to mature in cool fall weather.

How to sow the seeds

Sow seeds 1/4 inch deep in a sterile, well-drained seed-starting mix. Use individual cells or small pots with drainage, and pot up only if seedlings outgrow their cells before planting time.

Germination

Cauliflower usually germinates in 4 to 10 days. Keep the mix evenly moist and warm, about 65 to 75°F, until sprouts emerge.

Seedling care

Give seedlings bright light immediately after germination and moderate temperatures to limit legginess. Water when the mix begins to dry at the surface, ensure airflow, and thin each cell to one healthy plant to help prevent damping off.

Transplanting & hardening off

Harden off plants for 7 to 10 days, then transplant when they have 4 to 6 true leaves and cool weather is expected. Plant at the same depth as in the container, space according to the variety, and water thoroughly after setting out.

Tips

Keep seedling growth steady, because severe stress can lead to small or poorly formed heads. Label varieties carefully, since spring and fall types may perform differently.

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