When to plant swiss chard in London
Swiss chard is cold-hardy, so every date keys off London's frost dates of Apr 10.
Step 1 · Sow
Start seeds indoors
Mar 13 – Apr 3
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 27 – Apr 17
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
May 16 – May 26
Picking runs until conditions turn against the crop.
Window
Days to maturity
50 – 60 d
London's 209-day season leaves this much room.
Swiss chard 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 swiss chard outdoors in London?
Direct-sow around late March (Mar 27–Apr 17) in London, based on its local frost dates. Confidence 88%.
When will swiss chard be ready to harvest in London?
Expect to harvest from around mid May (May 16–May 26) in London, based on its local frost dates. Confidence 79%.
When should I start swiss chard seeds indoors in London?
Start seeds indoors around mid March (Mar 13–Apr 3) in London, based on its local frost dates. Confidence 84%.
When can I transplant swiss chard outdoors in London?
Transplant outdoors around late March (Mar 27–Apr 17) 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 swiss chard to maturity outdoors.
The rule of thumb
Sow swiss chard 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 London's frost dates.
Confidence 88/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.