When to plant sweet corn in Washington
Sweet corn is frost-tender, so every date keys off Washington's last spring frost of Mar 24.
Step 1 · Sow
Direct sow outdoors
Apr 30 – May 21
Sow straight into warm, workable soil.
Step 2 · Harvest
Harvest window
Jun 29 – Aug 8
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 100 d
Washington's 234-day season leaves this much room.
Sweet corn on Washington's growing year
Frost-bounded season with crops mapped onto the 12-month axis.
Frost risk Growing Harvest
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
FROST
FROST
HARVEST
MAR 24
NOV 17
Common questions
When can I sow sweet corn outdoors in Washington?
Direct-sow around late April (Apr 30–May 21) in Washington, based on its local frost dates. Confidence 86%.
When will sweet corn be ready to harvest in Washington?
Expect to harvest from around late June (Jun 29–Aug 8) in Washington, based on its local frost dates. Confidence 80%.
How long is the growing season in Washington?
Washington has roughly 234 frost-free days, which is enough time to grow sweet corn to maturity outdoors.
The rule of thumb
Sow sweet corn 6–8 weeks before your last spring frost; plant out 2–3 weeks after it. Every date on this page is derived from that rule and Washington's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.