Start indoors or direct sow?

Start basil indoors and transplant it for an earlier harvest, or direct sow after warm weather arrives. It is tender and should not go outside until frost danger has passed and the soil has warmed.

When to start Basil seeds

Start indoor seeds 4 to 6 weeks before the last spring frost. Direct sow 1 to 2 weeks after the last frost, once nighttime temperatures are reliably mild.

How to sow the seeds

Sow seeds 1/4 inch deep in a sterile seed-starting mix, using small cells or 2-inch pots. Keep the mix lightly moist and place indoor containers on a heat mat or in a warm location until seedlings emerge.

Germination

Basil usually germinates in 5 to 10 days. Soil near 70 to 85 F and even, light moisture promote fast germination.

Seedling care

Give seedlings strong light, ideally 14 to 16 hours under grow lights, and water when the mix surface begins to dry. Provide airflow, avoid soggy mix, and thin or separate seedlings so each cell has one strong plant to reduce damping off.

Transplanting & hardening off

Harden plants off for 7 to 10 days after the last frost, gradually increasing their outdoor exposure. Transplant into full sun after soil is warm, setting plants at the same depth they grew in their containers.

Tips

Pinch the growing tip after plants have several sets of true leaves to encourage branching. Do not rush basil into cool soil, since chilling can stall it.

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