When to plant basil in London
Basil is frost-tender, so every date keys off London's last spring frost of Apr 10.
Step 1 · Sow
Start seeds indoors
Mar 6 – Mar 27
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 17 – May 8
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 16 – Jul 16
Picking runs until conditions turn against the crop.
Window
Days to maturity
60 – 90 d
London's 209-day season leaves this much room.
Basil on London'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 10
NOV 5
Common questions
When can I sow basil outdoors in London?
Direct-sow around mid April (Apr 17–May 8) in London, based on its local frost dates. Confidence 88%.
When will basil be ready to harvest in London?
Expect to harvest from around mid June (Jun 16–Jul 16) in London, based on its local frost dates. Confidence 79%.
When should I start basil seeds indoors in London?
Start seeds indoors around early March (Mar 6–Mar 27) in London, based on its local frost dates. Confidence 84%.
When can I transplant basil outdoors in London?
Transplant outdoors around mid April (Apr 17–May 8) in London, based on its local frost dates. Confidence 88%.
How long is the growing season in London?
London has roughly 209 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 London's frost dates.
Confidence 88/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.