New Hampshire · zones 4b–6a
When to plant spinach in New Hampshire.
Sow between Mar 24 to May 5 in a typical year, keyed to New Hampshire's median last frost around May 15. A second, fall sowing fits Jul 15 to Sep 2. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Spinach dates for a typical New Hampshire season.
Direct sow
Mar 24 to May 5
Keyed to the ~May 15 last frost. Sow 0.5" deep, 3" apart.
Fall round
Jul 15 to Sep 2
Counted back from the ~Sep 28 first frost.
Harvest
~42 days later
~0.25 lb per plant over ~1 weeks.
New Hampshire spans more than one climate: Zone 5 is the most common zone, but the state runs 4b to 6a. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
In New Hampshire: watch for
The pests that find spinach here.
The short season here, about 136 frost-free days, keeps spinach in front of leaf miners only briefly. One early row cover usually carries a planting through the worst of it.
Winding pale tunnels or blotches inside the leaves.
Organic fix: Pick and destroy mined leaves; cover the row.
Cercospora leaf spot
Round spots with gray centers and a red-purple rim, oldest leaves worst.
Organic fix: Space wider so leaves dry fast, clear old debris, and pull pigweed and lambsquarters nearby.
Your season math: New Hampshire gives spinach about 136 frost-free days, and it needs roughly 42 days to a first harvest. That fits about 14 re-sown rounds across the season, so you can keep it coming instead of picking once.
Planting spinach in New Hampshire: questions
When should I plant spinach in New Hampshire?+
In a typical New Hampshire year, sow spinach between Mar 24 to May 5, keyed to the state's median last frost around May 15. There's also a fall window: Jul 15 to Sep 2. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is New Hampshire?+
New Hampshire spans zones 4b–6a, mostly zone 5. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many spinach plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.