When to plant zucchini / summer squash 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). Zucchini / Summer Squash needs 45–60 days to mature, which fits comfortably within Indiana's growing season.
When to plant zucchini / summer squash in Indiana: the short answer
For a spring planting, plant out Apr 24 – May 11, with seeds started indoors Mar 27 – Apr 10. Wait until the soil is at least 60°F and frost is over.
Succession sow again in Indiana: May 29 · Jun 26 · Jul 24
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 zucchini / summer squash in Indiana, step by step
- Start seeds indoors (Mar 27 – Apr 10). Sow seeds 1 inch deep in seed-starting mix under bright light. They take 5-10 days to sprout, fastest in soil around 85°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 14 inches deep, with a pH between 5.5 and 7.5. Dig in compost before planting.
- Plant out (Apr 24 – May 11). Space plants about 30 inches apart in rows 42 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: squash vine borer, squash bug, striped cucumber beetle, aphids. Diseases and disorders: powdery mildew, bacterial wilt, blossom-end rot (calcium disorder).
- Harvest (from about Jun 15 – Jun 30). Zucchini / Summer Squash takes 45-60 days to reach harvest. One or two plants feed a household. A second sowing in early-mid summer dodges the first vine borer generation.
Figures come from our crop data; dates use Indiana’s average frost dates. More in the full zucchini / summer squash growing guide.
Zucchini 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 zucchini / summer squash dates shift with them.
When to plant zucchini / summer squash in nearby states
Questions gardeners in Indiana ask
When is the best time to plant zucchini / summer squash in Indiana?
Plant zucchini / summer squash transplants outdoors in Indiana between April 24 and May 11. That timing is set by Indiana's average last spring frost of April 24.
When should I start zucchini / summer squash seeds indoors in Indiana?
Start seeds indoors between March 27 and April 10, about 3 weeks before the last frost, so the seedlings are ready to plant out from April 24.
Can I plant zucchini / summer squash in the fall in Indiana?
Yes. For a fall crop, sow between July 9 and July 26, so the crop matures in cool weather before Indiana's first frost around October 11.
When will zucchini / summer squash planted in Indiana be ready to harvest?
Planted on time, zucchini / summer squash is usually ready from about June 15 to June 30, 45-60 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.