When to plant broccoli in Missoula
Broccoli is cold-hardy, so every date keys off Missoula's frost dates of May 15.
Step 1 · Sow
Start seeds indoors
Apr 3 – Apr 24
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
May 1 – May 22
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jun 30 – Jul 25
Picking runs until conditions turn against the crop.
Step 4 · Second sowing
Autumn / second sowing
Jun 20 – Jul 4
A second window for a fall crop, timed to mature before the first frost.
Step 5 · Second harvest
Autumn crop harvest
Aug 26 – Sep 20
Maturity window for the second sowing.
Window
Days to maturity
60 – 85 d
Missoula's 138-day season leaves this much room.
Broccoli on Missoula'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 15
OCT 4
Common questions
When will broccoli be ready to harvest in Missoula?
Expect to harvest from around late June (Jun 30–Jul 25) in Missoula, based on its local frost dates. Confidence 75%.
When should I start broccoli seeds indoors in Missoula?
Start seeds indoors around early April (Apr 3–Apr 24) in Missoula, based on its local frost dates. Confidence 79%.
When can I transplant broccoli outdoors in Missoula?
Transplant outdoors around early May (May 1–May 22) in Missoula, based on its local frost dates. Confidence 83%.
Can I plant broccoli in autumn in Missoula?
Yes — Missoula supports a second, autumn sowing of broccoli around mid June (Jun 20–Jul 4), timed to mature before the first fall frost.
How long is the growing season in Missoula?
Missoula has roughly 138 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 Missoula's frost dates.
Confidence 83/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.