When to plant pumpkins in Manchester, New Hampshire

May 20 – June 3

Transplant outdoors · typical Manchester year

Climate basis: NOAA station Massabesic Lake, NH (USC00275211), 4 mi (6 km) from downtown Manchester (ZCTA 03101 centroid), elevation 253 ft, on the 1991–2020 climate normals. Transplant pumpkins outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (April 30). One year in ten still freezes after May 14.

Last spring freezeApril 301-in-10 after May 14

First fall freezeOctober 111-in-10 before Sep 30

Frost-free season≈ 164 daysmedian at 32°F

Hard freeze, 28°Apr 17 – Oct 24kills even hardy greens

USDA zone6a-10 to -5°F winter low — not frost timing

The Manchester year

Start seeds indoorsApr 8 – Apr 22

Transplant outdoorsMay 20 – Jun 3

Direct-sow outdoorsMay 20 – Jun 3

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to May 14

Pumpkins in Manchester · freeze context from Massabesic Lake, NH, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Apr 8 – Apr 22

Sow in pots 4–6 weeks before the outdoor window opens (Missouri G6570: 4–6 weeks). Anchored to the median last spring freeze (Apr 30). University of Missouri Extension

Transplant outdoors

May 20 – Jun 3

Same outdoor timing as direct seeding, using pot-grown transplants. Anchored to the median last spring freeze (Apr 30). Penn State Extension (York County Master Gardeners) · Purdue University Extension · University of Missouri Extension

Direct-sow outdoors

May 20 – Jun 3

Purdue: very tender — at least two weeks after the last frost; Penn State's earliest sowing May 21 (+20 days) is the later start and is used. Anchored to the median last spring freeze (Apr 30). Penn State Extension (York County Master Gardeners) · Purdue University Extension

Variety assumption: Assumes an average carving variety (about 100–115 days; Penn State lists 110). For Halloween pumpkins, sow toward the start of the window.

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:

Crop rule sources (3)

University of Missouri Extension: Starting Plants Indoors from Seeds (G6570) (accessed 2026-07-24)
Weeks needed to grow vegetable transplants indoors (Table 2).
Penn State Extension (York County Master Gardeners): Vegetable Seed Planting Guide (accessed 2026-07-24)
Earliest/latest sowing dates for a May 1 last-frost / Oct 1 first-frost baseline; offsets derived by date difference from May 1. Also days-to-maturity figures.
Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)
Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.

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