When to plant sweet corn in Ottawa
Sweet corn is frost-tender, so every date keys off Ottawa's last spring frost of May 6.
Step 1 · Sow
Direct sow outdoors
May 13 – Jun 3
Sow straight into warm, workable soil.
Step 2 · Harvest
Harvest window
Jul 12 – Aug 21
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 100 d
Ottawa's 149-day season leaves this much room.
Sweet corn on Ottawa'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
MAY 6
OCT 2
Common questions
When can I sow sweet corn outdoors in Ottawa?
Direct-sow around mid May (May 13–Jun 3) in Ottawa, based on its local frost dates. Confidence 84%.
When will sweet corn be ready to harvest in Ottawa?
Expect to harvest from around mid July (Jul 12–Aug 21) in Ottawa, based on its local frost dates. Confidence 76%.
How long is the growing season in Ottawa?
Ottawa has roughly 149 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 Ottawa's frost dates.
Confidence 84/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.