When to plant broccoli in Chicago
Broccoli is cold-hardy, so every date keys off Chicago's frost dates of Apr 10.
Step 1 · Sow
Start seeds indoors
Feb 27 – Mar 20
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 26 – Jun 20
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Jul 17 – Jul 31
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Sep 22 – Oct 17
Maturity window for the second sowing.
Window
Days to maturity
60 – 85 d
Chicago's 206-day season leaves this much room.
Broccoli on Chicago'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
OCT 31
Common questions
When will broccoli be ready to harvest in Chicago?
Expect to harvest from around late May (May 26–Jun 20) in Chicago, based on its local frost dates. Confidence 76%.
When should I start broccoli seeds indoors in Chicago?
Start seeds indoors around late February (Feb 27–Mar 20) in Chicago, based on its local frost dates. Confidence 80%.
When can I transplant broccoli outdoors in Chicago?
Transplant outdoors around late March (Mar 27–Apr 17) in Chicago, based on its local frost dates. Confidence 84%.
Can I plant broccoli in autumn in Chicago?
Yes — Chicago supports a second, autumn sowing of broccoli around mid July (Jul 17–Jul 31), timed to mature before the first fall frost.
How long is the growing season in Chicago?
Chicago has roughly 206 frost-free days, which is enough time to grow broccoli to maturity outdoors.
The rule of thumb
Sow broccoli 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 Chicago's frost dates.
Confidence 84/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.