When to plant basil in Indiana
Indiana’s average last spring frost is April 24, and the first fall frost typically arrives around October 11 — about 170 frost-free days (USDA zones 5b, 6a, 6b). Basil needs 30–60 days to mature, which fits comfortably within Indiana's growing season.
When to plant basil in Indiana: the short answer
For a spring planting, plant out May 1 – May 18, with seeds started indoors Mar 13 – Mar 27. Wait until the soil is at least 65°F and frost is over.
Succession sow again in Indiana: May 29 · Jun 19 · Jul 10 · Jul 31 · Aug 21
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 Indiana, step by step
- Start seeds indoors (Mar 13 – Mar 27). 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.
- Plant out (May 1 – May 18). Space plants about 10 inches apart in rows 12 inches apart. 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 Jun 7 – Jul 7). 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 Indiana’s average frost dates. More in the full basil growing guide.
Basil planting dates by USDA zone in Indiana
Indiana spans USDA zones 5b, 6a, 6b. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the basil dates shift with them.
When to plant basil in nearby states
Questions gardeners in Indiana ask
When is the best time to plant basil in Indiana?
Plant basil transplants outdoors in Indiana between May 1 and May 18. That timing is set by Indiana's average last spring frost of April 24.
When should I start basil seeds indoors in Indiana?
Start seeds indoors between March 13 and March 27, about 5 weeks before the last frost, so the seedlings are ready to plant out from May 1.
What is the latest I can plant basil in Indiana?
About September 11. Basil needs at least 30 days to mature, and frost around October 11 ends the season, so later plantings risk being cut short.
When will basil planted in Indiana be ready to harvest?
Planted on time, basil is usually ready from about June 7 to July 7, 30-60 days after planting.
When is the last frost in Indiana?
On average around April 24, with the first fall frost around October 11 - about 170 frost-free days. Your town may differ by two weeks or more.