New Hampshire planting calendar

When to plant spinach in New Hampshire — sow, transplant & harvest dates

New Hampshire is mostly USDA zone 5b (range 3b-6a). Dates below are derived from spinach's frost tolerance and New Hampshire's frost window — not generic national averages.

Spinach planting timetable for New Hampshire

Stage	When in New Hampshire	Anchor
Direct-sow outside	early April (April 10)	35 days before the last frost (mid-May)
First harvest (estimate)	late May (May 25)	~45 days from direct sow

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why New Hampshire's climate shifts the spinach dates

New Hampshire's last spring frost averages mid-May and first fall frost late September, which sets the whole planting clock. New Hampshire is a cold New England state with a brief but reliable summer, milder along the small seacoast and colder in the mountains. Sow early — spinach bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Spinach is direct-sown only — it does not transplant well and runs to seed quickly under any stress. Sow as soon as soil can be worked, 4–6 weeks before the last spring frost; it germinates in soil as cold as 4 °C and seedlings survive light freezes to -6 °C. Bolt risk rises sharply once daytime temperatures consistently exceed 24 °C or day length passes 14 hours, so succession-sow every 2 weeks and switch to heat-tolerant varieties in late spring. In Zones 7–10, a second sowing in late summer or early fall produces the best crop of the year.

Frost-risk note

Don't plant before mid-May — a hard freeze can still set young plants back. In the White Mountains and far north (zone 3b) the safe date runs a week or two later.

Regional variation within New Hampshire

the White Mountains and far north (zone 3b) runs roughly 1-2 weeks behind the state average; the short Atlantic seacoast near Portsmouth (zone 6a) can plant 1-2 weeks earlier.

Manchester — USDA zone 5b
Concord — USDA zone 5b
Nashua — USDA zone 5b
Portsmouth — USDA zone 6a

What else to plant in New Hampshire around then

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun to partial shade.
Soil temperature for germination: 4-21 °C (40-70 °F).
Spacing: 3-6 inches (8-15 cm) between plants.
Days to harvest: ~45 days from planting out.

Frequently asked questions

When is the best time to plant spinach in New Hampshire?

In New Hampshire (mostly USDA zone 5b), direct-sow spinach early April (before the last frost, mid-May), and harvest from late May. Spinach are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

What USDA zone is New Hampshire?

Most of New Hampshire sits in USDA hardiness zone 5b, with the state spanning roughly 3b-6a from the White Mountains and far north (zone 3b) to the short Atlantic seacoast near Portsmouth (zone 6a). The last spring frost averages mid-May and the first fall frost late September.

Can you grow spinach in New Hampshire?

Yes. New Hampshire's dominant zone 5b supports spinach — the key is timing. Spinach are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across New Hampshire?

the White Mountains and far north (zone 3b) runs roughly 1-2 weeks behind the state average; the short Atlantic seacoast near Portsmouth (zone 6a) can plant 1-2 weeks earlier.

What else can I plant in New Hampshire around the same time?

The same early window suits peas, lettuce, spinach, and onion sets.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.