When to plant garlic in Ottawa
Garlic is cold-hardy, so every date keys off Ottawa's frost dates of Apr 29.
Step 1 · Sow
Direct sow outdoors
Sep 10 – Oct 1
Sow straight into warm, workable soil.
Step 2 · Harvest
Harvest window
May 8 – May 8
Picking runs until conditions turn against the crop.
Window
Days to maturity
240 d
Ottawa's 161-day season leaves this much room.
Garlic 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 garlic outdoors in Ottawa?
Direct-sow around early September (Sep 10–Oct 1) in Ottawa, based on its local frost dates. Confidence 89%.
When will garlic be ready to harvest in Ottawa?
Expect to harvest from around early May (May 8–May 8) in Ottawa, based on its local frost dates. Confidence 80%.
How long is the growing season in Ottawa?
Ottawa has roughly 161 frost-free days, which is marginal time to grow garlic to maturity outdoors.
The rule of thumb
Sow garlic as soon as the soil is workable — it tolerates cool weather and light frost. 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.