When to plant zucchini / summer squash in District of Columbia
District of Columbia’s average last spring frost is April 10, and the first fall frost typically arrives around October 25 — about 198 frost-free days (USDA zones 7a, 7b, 8a). Zucchini / Summer Squash needs 45–60 days to mature, which fits comfortably within District of Columbia's growing season.
When to plant zucchini / summer squash in District of Columbia: the short answer
For a spring planting, plant out Apr 10 – Apr 27, with seeds started indoors Mar 13 – Mar 27. Wait until the soil is at least 60°F and frost is over.
Succession sow again in District of Columbia: May 15 · Jun 12 · Jul 10 · Aug 7
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 District of Columbia, step by step
- Start seeds indoors (Mar 13 – Mar 27). 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 10 – Apr 27). 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 1 – Jun 16). 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 District of Columbia’s average frost dates. More in the full zucchini / summer squash growing guide.
Zucchini planting dates by USDA zone in District of Columbia
District of Columbia spans USDA zones 7a, 7b, 8a. 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
| State | Last frost | Plant out |
|---|---|---|
| District of Columbia (this page) | April 10 | Apr 10 – Apr 27 |
| New Jersey | April 20 | Apr 20 – May 7 |
| Pennsylvania | May 1 | May 1 – May 18 |
| Delaware | April 14 | Apr 14 – May 1 |
| Maryland | April 14 | Apr 14 – May 1 |
| Virginia | April 15 | Apr 15 – May 2 |
| West Virginia | May 5 | May 5 – May 22 |
Questions gardeners in District of Columbia ask
When is the best time to plant zucchini / summer squash in District of Columbia?
Plant zucchini / summer squash transplants outdoors in District of Columbia between April 10 and April 27. That timing is set by District of Columbia's average last spring frost of April 10.
When should I start zucchini / summer squash seeds indoors in District of Columbia?
Start seeds indoors between March 13 and March 27, about 3 weeks before the last frost, so the seedlings are ready to plant out from April 10.
Can I plant zucchini / summer squash in the fall in District of Columbia?
Yes. For a fall crop, sow between July 23 and August 9, so the crop matures in cool weather before District of Columbia's first frost around October 25.
When will zucchini / summer squash planted in District of Columbia be ready to harvest?
Planted on time, zucchini / summer squash is usually ready from about June 1 to June 16, 45-60 days after planting.
When is the last frost in District of Columbia?
On average around April 10, with the first fall frost around October 25 - about 198 frost-free days. Your town may differ by two weeks or more.