When to plant swiss chard in Modesto

Swiss chard is cold-hardy, so every date keys off Modesto's frost dates of Jan 27.
Step 1 · Sow
Start seeds indoors
Dec 30 – Jan 20
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Dec 26 – Jan 16
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Feb 14 – Feb 24
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Sep 1 – Sep 15
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Oct 28 – Nov 7
Maturity window for the second sowing.
Window
Days to maturity
50 – 60 d
Modesto's 310-day season leaves this much room.
Swiss chard on Modesto'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
JAN 27
DEC 3

Common questions

When can I sow swiss chard outdoors in Modesto?

Direct-sow around late December (Dec 26–Jan 16) in Modesto, based on its local frost dates. Confidence 84%.

When will swiss chard be ready to harvest in Modesto?

Expect to harvest from around mid February (Feb 14–Feb 24) in Modesto, based on its local frost dates. Confidence 78%.

When should I start swiss chard seeds indoors in Modesto?

Start seeds indoors around late December (Dec 30–Jan 20) in Modesto, based on its local frost dates. Confidence 83%.

When can I transplant swiss chard outdoors in Modesto?

Transplant outdoors around late December (Dec 26–Jan 16) in Modesto, based on its local frost dates. Confidence 84%.

Can I plant swiss chard in autumn in Modesto?

Yes — Modesto supports a second, autumn sowing of swiss chard around early September (Sep 1–Sep 15), timed to mature before the first fall frost.

How long is the growing season in Modesto?

Modesto has roughly 310 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 Modesto's frost dates.

Confidence 87/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.