When to plant broccoli in Duluth
Broccoli is cold-hardy, so every date keys off Duluth's frost dates of May 10.
Step 1 · Sow
Start seeds indoors
Mar 29 – Apr 19
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 2 – May 23
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 1 – Jul 26
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Jun 23 – Jul 7
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Aug 29 – Sep 23
Maturity window for the second sowing.
Window
Days to maturity
60 – 85 d
Duluth's 150-day season leaves this much room.
Broccoli on Duluth'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
MAY 10
OCT 7
Common questions
When will broccoli be ready to harvest in Duluth?
Expect to harvest from around early July (Jul 1–Jul 26) in Duluth, based on its local frost dates. Confidence 78%.
When should I start broccoli seeds indoors in Duluth?
Start seeds indoors around late March (Mar 29–Apr 19) in Duluth, based on its local frost dates. Confidence 83%.
When can I transplant broccoli outdoors in Duluth?
Transplant outdoors around early May (May 2–May 23) in Duluth, based on its local frost dates. Confidence 84%.
Can I plant broccoli in autumn in Duluth?
Yes — Duluth supports a second, autumn sowing of broccoli around late June (Jun 23–Jul 7), timed to mature before the first fall frost.
How long is the growing season in Duluth?
Duluth has roughly 150 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 Duluth's frost dates.
Confidence 87/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.