When to plant garlic in Ottawa
Garlic is cold-hardy, so every date keys off Ottawa's frost dates of May 6.
Step 1 · Sow
Direct sow outdoors
Sep 4 – Sep 25
Sow straight into warm, workable soil.
Step 2 · Harvest
Harvest window
May 1 – May 1
Picking runs until conditions turn against the crop.
Window
Days to maturity
240 d
Ottawa's 149-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
MAY 6
OCT 2
Common questions
When can I sow garlic outdoors in Ottawa?
Direct-sow around early September (Sep 4–Sep 25) in Ottawa, based on its local frost dates. Confidence 84%.
When will garlic be ready to harvest in Ottawa?
Expect to harvest from around early May (May 1–May 1) 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 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 84/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.