When to plant basil in Boston
Basil is frost-tender, so every date keys off Boston's last spring frost of Apr 4.
Step 1 · Sow
Start seeds indoors
Mar 11 – Apr 1
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Jun 3 – Jun 24
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Aug 2 – Sep 1
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 90 d
Boston's 220-day season leaves this much room.
Basil on Boston'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 4
NOV 9
Common questions
When can I sow basil outdoors in Boston?
Direct-sow around early June (Jun 3–Jun 24) in Boston, based on its local frost dates. Confidence 86%.
When will basil be ready to harvest in Boston?
Expect to harvest from around early August (Aug 2–Sep 1) in Boston, based on its local frost dates. Confidence 80%.
When should I start basil seeds indoors in Boston?
Start seeds indoors around mid March (Mar 11–Apr 1) in Boston, based on its local frost dates. Confidence 85%.
When can I transplant basil outdoors in Boston?
Transplant outdoors around early June (Jun 3–Jun 24) in Boston, based on its local frost dates. Confidence 86%.
How long is the growing season in Boston?
Boston has roughly 220 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 Boston's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.