When to plant basil in Hawaii
Hawaii is essentially frost-free (USDA zones 9b, 10a, 10b, 11a, 11b, 12a, 12b, 13a), so basil timing there is set by heat and daylength rather than frost. As a warm-season crop, the main risk is mid-summer heat — spring and late-summer plantings usually do best.
Hawaii covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant basil in Hawaii: the short answer
For a spring planting, sow Feb 10 – Mar 1, with seeds started indoors Dec 21 – Jan 4. Wait until the soil is at least 65°F and frost is over.
Your area is essentially frost-free, so planting dates are set by heat and daylength rather than frost. Treat the ranges below as broad season guides.
Warm-season crop: in a frost-free area the main risk is mid-summer heat; spring and late-summer plantings usually do best.
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow basil in Hawaii, step by step
- Start seeds indoors (Dec 21 – Jan 4). Sow seeds ⅛ inch deep in seed-starting mix under bright light. They take 5-10 days to sprout, fastest in soil around 80°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. It needs at least six to eight hours of direct sun a day and loose soil at least 10 inches deep, with a pH between 6.0 and 7.0. Dig in compost before planting.
- Sow outdoors (Feb 10 – Mar 1). Space plants about 10 inches apart in rows 12 inches apart, sowing seed ⅛ inch deep. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: aphids, Japanese beetle, slugs. Diseases and disorders: basil downy mildew, fusarium wilt, damping off.
- Harvest (from about Mar 17 – Apr 16). Basil takes 30-60 days to reach harvest. Cold soil stalls it - wait for warm nights. Pinch above a leaf pair every couple of weeks and remove flower buds to keep leaves coming. Downy mildew-resistant varieties are worth seeking out.
Figures come from our crop data; dates use Hawaii’s average frost dates. More in the full basil growing guide.