When to plant cucumbers in New Hampshire
New Hampshire’s average last spring frost is May 13, and the first fall frost typically arrives around September 25 — about 135 frost-free days (USDA zones 3b, 4a, 4b, 5a, 5b, 6a). Cucumber needs 50–70 days to mature, which fits comfortably within New Hampshire's growing season.
When to plant cucumbers in New Hampshire: the short answer
For a spring planting, plant out May 20 – Jun 6, with seeds started indoors Apr 15 – Apr 29. Wait until the soil is at least 60°F and frost is over.
Succession sow again in New Hampshire: Jun 17 · Jul 8
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 cucumbers in New Hampshire, step by step
- Start seeds indoors (Apr 15 – Apr 29). Sow seeds 1 inch deep in seed-starting mix under bright light. They take 3-10 days to sprout, fastest in soil around 85°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. They need 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 7.0. Dig in compost before planting.
- Plant out (May 20 – Jun 6). Space plants about 12 inches apart in rows 48 inches apart. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. It needs plenty of water; keep the soil evenly moist and never let it dry out.
- Watch for pests and problems. Pests: striped cucumber beetle, squash bug, aphids, spider mite. Diseases and disorders: powdery mildew, downy mildew, bacterial wilt, angular leaf spot.
- Harvest (from about Jul 16 – Aug 5). Cucumber takes 50-70 days to reach harvest. Resents root disturbance - if starting indoors use peat/paper pots. Trellising doubles the plants per square foot and cuts disease. A second sowing in midsummer beats early beetle pressure.
Figures come from our crop data; dates use New Hampshire’s average frost dates. More in the full cucumber growing guide.
Cucumber planting dates by USDA zone in New Hampshire
New Hampshire spans USDA zones 3b, 4a, 4b, 5a, 5b, 6a. 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 cucumber dates shift with them.
When to plant cucumbers in nearby states
| State | Last frost | Plant out |
|---|---|---|
| New Hampshire (this page) | May 13 | May 20 – Jun 6 |
| Maine | May 14 | May 21 – Jun 7 |
| Vermont | May 14 | May 21 – Jun 7 |
| Massachusetts | April 24 | May 1 – May 18 |
| Rhode Island | April 25 | May 2 – May 19 |
| Connecticut | April 25 | May 2 – May 19 |
| New York | May 1 | May 8 – May 25 |
Questions gardeners in New Hampshire ask
When is the best time to plant cucumbers in New Hampshire?
Plant cucumber transplants outdoors in New Hampshire between May 20 and June 6. That timing is set by New Hampshire's average last spring frost of May 13.
When should I start cucumber seeds indoors in New Hampshire?
Start seeds indoors between April 15 and April 29, about 3 weeks before the last frost, so the seedlings are ready to plant out from May 20.
Can I plant cucumbers in the fall in New Hampshire?
Yes. For a fall crop, sow between June 23 and July 10, so the crop matures in cool weather before New Hampshire's first frost around September 25.
When will cucumbers planted in New Hampshire be ready to harvest?
Planted on time, cucumbers are usually ready from about July 16 to August 5, 50-70 days after planting.
When is the last frost in New Hampshire?
On average around May 13, with the first fall frost around September 25 - about 135 frost-free days. Your town may differ by two weeks or more.