Manchester, NH 03032 planting calendar
- USDA zone
- 6a−10 to −5 °F
- Last frost
- Apr 30avg, 32°F
- First frost
- Oct 11avg, 32°F
- Growing season
- 164days
Manchester, New Hampshire is in USDA plant hardiness zone 6a. Its average last spring frost is around April 30 and the first fall frost around October 11, giving a growing season of about 164 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Manchester planting calendar
Each crop's windows are counted from Manchester's average frost dates. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Mar 5 – Mar 19 | May 7 – May 14 | Jul 6 – Jul 26 | — |
| Pepper | Very tender | Feb 19 – Mar 5 | May 14 – May 21 | Jul 13 – Aug 12 | — |
| Cucumber | Tender | Apr 2 – Apr 9 | May 7 – May 14 | Jun 26 – Jul 16 | — |
| Summer squash / zucchini | Tender | — | May 7 – May 14 | Jun 21 – Jul 6 | — |
| Bush bean | Tender | — | May 7 – May 14 | Jun 26 – Jul 6 | Aug 12 – Aug 22 |
| Sweet corn | Tender | — | Apr 30 – May 14 | Jun 29 – Jul 29 | — |
| Basil | Very tender | Mar 19 – Apr 2 | May 7 – May 14 | Jun 6 – Jun 21 | — |
| Lettuce | Half-hardy | Mar 19 – Apr 2 | Apr 2 – Apr 16 | May 17 – Jun 1 | Jul 29 – Aug 13 |
| Pea | Hardy | — | Mar 19 – Apr 2 | May 13 – May 28 | Jul 19 – Aug 3 |
| Spinach | Hardy | — | Mar 19 – Apr 2 | Apr 28 – May 8 | Aug 8 – Aug 18 |
| Carrot | Half-hardy | — | Apr 9 – Apr 16 | Jun 8 – Jun 28 | Jul 9 – Jul 29 |
| Broccoli | Half-hardy | Mar 5 – Mar 19 | Apr 2 – Apr 16 | May 27 – Jun 16 | Jul 14 – Aug 3 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USC00275211. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 (p10 for spring, p90 for fall) — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | May 12 | May 24 | Oct 2 | Oct 14 | 141 |
| 32°F (freeze) | Apr 30 | May 14 | Oct 11 | Oct 27 | 164 |
| 28°F | Apr 17 | May 2 | Oct 24 | Nov 8 | 188 |
| 24°F | Apr 5 | Apr 18 | Nov 5 | Nov 22 | 213 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 2,496 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,490 | cool-season crops (brassicas, greens) |
Hardiness zone 6a
Manchester sits in USDA plant hardiness zone 6a on the 2023 map — meaning its average annual extreme minimum winter temperature is about −10 to −5 °F. That number tells you which perennials, shrubs, and trees reliably survive an average winter here; it does not set your planting dates, which come from the frost calendar above.
Explore more places in zone 6a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Manchester?
- Manchester, New Hampshire is in USDA plant hardiness zone 6a on the 2023 map (average annual extreme minimum temperature −10 to −5 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Manchester?
- The average (median) last spring frost at 32°F is around April 30, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as May 14, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Manchester?
- The average first fall frost at 32°F is around October 11. That leaves a growing season of about 164 days between the average last spring and first fall frosts.
- When should I start tomatoes in Manchester?
- Start tomato seeds indoors about Mar 5 – Mar 19 and transplant them outside about May 7 – May 14, once the danger of frost has passed. Estimated first harvest is around Jul 6 – Jul 26.
- How long is the growing season in Manchester?
- About 164 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~April 30) and the average first fall frost (~October 11). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USC00275211 (Massabesic Lake, 2.4 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.