When to plant melon (cantaloupe/watermelon) in Ottawa
Melon (cantaloupe/watermelon) is frost-tender, so every date keys off Ottawa's last spring frost of Apr 29.
Step 1 · Sow
Start seeds indoors
Apr 20 – May 11
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jul 6 – Jul 27
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Sep 19 – Oct 14
Picking runs until conditions turn against the crop.
Window
Days to maturity
75 – 100 d
Ottawa's 161-day season leaves this much room.
Melon (cantaloupe/watermelon) 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
APR 29
OCT 8
Common questions
When can I sow melon (cantaloupe/watermelon) outdoors in Ottawa?
Direct-sow around early July (Jul 6–Jul 27) in Ottawa, based on its local frost dates. Confidence 86%.
When will melon (cantaloupe/watermelon) be ready to harvest in Ottawa?
Expect to harvest from around mid September (Sep 19–Oct 14) in Ottawa, based on its local frost dates. Confidence 80%.
When should I start melon (cantaloupe/watermelon) seeds indoors in Ottawa?
Start seeds indoors around mid April (Apr 20–May 11) in Ottawa, based on its local frost dates. Confidence 85%.
When can I transplant melon (cantaloupe/watermelon) outdoors in Ottawa?
Transplant outdoors around early July (Jul 6–Jul 27) in Ottawa, based on its local frost dates. Confidence 86%.
How long is the growing season in Ottawa?
Ottawa has roughly 161 frost-free days, which is enough time to grow melon (cantaloupe/watermelon) to maturity outdoors.
The rule of thumb
Sow melon (cantaloupe/watermelon) 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 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.