When to plant basil in Boise
Basil is frost-tender, so every date keys off Boise's last spring frost of May 2.
Step 1 · Sow
Start seeds indoors
Apr 10 – May 1
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 24 – Jun 14
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 23 – Aug 22
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 90 d
Boise's 168-day season leaves this much room.
Basil on Boise'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 2
OCT 17
Common questions
When can I sow basil outdoors in Boise?
Direct-sow around late May (May 24–Jun 14) in Boise, based on its local frost dates. Confidence 86%.
When will basil be ready to harvest in Boise?
Expect to harvest from around late July (Jul 23–Aug 22) in Boise, based on its local frost dates. Confidence 80%.
When should I start basil seeds indoors in Boise?
Start seeds indoors around early April (Apr 10–May 1) in Boise, based on its local frost dates. Confidence 85%.
When can I transplant basil outdoors in Boise?
Transplant outdoors around late May (May 24–Jun 14) in Boise, based on its local frost dates. Confidence 86%.
How long is the growing season in Boise?
Boise has roughly 168 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 Boise's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.