When to plant swiss chard in Seattle

Swiss chard is cold-hardy, so every date keys off Seattle's frost dates of Mar 17.
Step 1 · Sow
Start seeds indoors
Feb 17 – Mar 10
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Mar 3 – Mar 24
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Apr 22 – May 2
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Aug 10 – Aug 24
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Oct 6 – Oct 16
Maturity window for the second sowing.
Window
Days to maturity
50 – 60 d
Seattle's 237-day season leaves this much room.
Swiss chard on Seattle'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
MAR 17
NOV 13

Common questions

When can I sow swiss chard outdoors in Seattle?

Direct-sow around early March (Mar 3–Mar 24) in Seattle, based on its local frost dates. Confidence 83%.

When will swiss chard be ready to harvest in Seattle?

Expect to harvest from around late April (Apr 22–May 2) in Seattle, based on its local frost dates. Confidence 75%.

When should I start swiss chard seeds indoors in Seattle?

Start seeds indoors around mid February (Feb 17–Mar 10) in Seattle, based on its local frost dates. Confidence 79%.

When can I transplant swiss chard outdoors in Seattle?

Transplant outdoors around early March (Mar 3–Mar 24) in Seattle, based on its local frost dates. Confidence 83%.

Can I plant swiss chard in autumn in Seattle?

Yes — Seattle supports a second, autumn sowing of swiss chard around early August (Aug 10–Aug 24), timed to mature before the first fall frost.

How long is the growing season in Seattle?

Seattle has roughly 237 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 Seattle's frost dates.

Confidence 83/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.