When to plant basil in Portland
Basil is frost-tender, so every date keys off Portland's last spring frost of Mar 1.
Step 1 · Sow
Start seeds indoors
Feb 10 – Mar 3
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 5 – Jun 26
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Aug 4 – Sep 3
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 90 d
Portland's 266-day season leaves this much room.
Basil on Portland'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
MAR 1
NOV 22
Common questions
When can I sow basil outdoors in Portland?
Direct-sow around early June (Jun 5–Jun 26) in Portland, based on its local frost dates. Confidence 85%.
When will basil be ready to harvest in Portland?
Expect to harvest from around early August (Aug 4–Sep 3) in Portland, based on its local frost dates. Confidence 79%.
When should I start basil seeds indoors in Portland?
Start seeds indoors around early February (Feb 10–Mar 3) in Portland, based on its local frost dates. Confidence 84%.
When can I transplant basil outdoors in Portland?
Transplant outdoors around early June (Jun 5–Jun 26) in Portland, based on its local frost dates. Confidence 85%.
How long is the growing season in Portland?
Portland has roughly 266 frost-free days, which is enough time to grow basil to maturity outdoors.
The rule of thumb
Sow basil 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 Portland's frost dates.
Confidence 88/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.