When to plant sunflowers in New Hampshire

Sunflowers
Sow outdoors in Manchester
Apr 30–May 21

Across New Hampshire the window opens between April 29 and May 14. Find your city below; the dates follow each town's own average last frost.

Sow outdoors, Manchester
Apr 30–May 21
Last sowing for a harvest
Jun 19
Last frost, Manchester
Apr 30

Sow outdoors up to 3 weeks after the last frost. Sow every two weeks until midsummer for flowers through fall.

Sunflowers planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
JanFebMarAprMayJunJulAugSepOctNovDec
ManchesterApr 30–May 21
NashuaApr 29–May 20
ConcordMay 8–May 29
DoverMay 3–May 24
RochesterApr 30–May 21
KeeneMay 14–Jun 4
PortsmouthMay 4–May 25
DerryApr 30–May 21

Questions

When should I plant sunflowers in New Hampshire?

In Manchester, sow outdoors from April 30 to May 21. Across New Hampshire the window opens between April 29 and May 14, depending on the local last frost.

How is this date worked out?

Sow outdoors up to 3 weeks after the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.

More for New Hampshire

Sunflowers in other states

Frost dates for every city in New Hampshire