Start indoors or direct sow?

Direct sowing is preferred because arugula germinates and grows quickly in place. Indoor starts are possible, but they offer little advantage and should be transplanted while very young.

When to start Arugula seeds

Direct sow 2 to 4 weeks before the last spring frost, then sow every 1 to 2 weeks through cool weather. For an early transplant crop, start seeds indoors about 3 to 4 weeks before the last frost and set out 1 to 2 weeks before it.

How to sow the seeds

Sow seeds 1/4 inch deep in moist, fine-textured soil or seed-starting mix. For indoor starts, use small cells or shallow trays, and avoid letting roots become crowded before planting.

Germination

Arugula commonly emerges in 4 to 8 days. Soil around 55 to 75 F and consistent moisture support fast, even germination.

Seedling care

Provide bright light immediately after emergence and water gently whenever the mix begins to dry. Thin direct-sown plants to about 4 to 6 inches for individual plants, and use clean containers plus airflow to discourage damping off indoors.

Transplanting & hardening off

Indoor-raised arugula should be hardened off for about a week before planting. Move small seedlings outdoors at their original depth, spaced about 4 to 6 inches apart; direct-sown arugula does not need transplanting.

Tips

Choose a spot with afternoon shade during warm springs to extend the harvest. Pick leaves young for a milder flavor, and reseed after plants begin sending up flower stalks.

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