When to plant spinach in Portland
Spinach is cold-hardy, so every date keys off Portland's frost dates of May 1.
Step 1 · Sow
Direct sow outdoors
Apr 7 – Apr 28
Sow straight into warm, workable soil.
Step 2 · Harvest
Harvest window
May 17 – May 27
Picking runs until conditions turn against the crop.
Step 3 · Second sowing
Autumn / second sowing
Jul 31 – Aug 14
A second window for a fall crop, timed to mature before the first frost.
Step 4 · Second harvest
Autumn crop harvest
Sep 16 – Sep 26
Maturity window for the second sowing.
Window
Days to maturity
40 – 50 d
Portland's 165-day season leaves this much room.
Spinach on Portland'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 1
OCT 10
Common questions
When can I sow spinach outdoors in Portland?
Direct-sow around early April (Apr 7–Apr 28) in Portland, based on its local frost dates. Confidence 86%.
When will spinach be ready to harvest in Portland?
Expect to harvest from around mid May (May 17–May 27) in Portland, based on its local frost dates. Confidence 80%.
Can I plant spinach in autumn in Portland?
Yes — Portland supports a second, autumn sowing of spinach around late July (Jul 31–Aug 14), timed to mature before the first fall frost.
How long is the growing season in Portland?
Portland has roughly 165 frost-free days, which is enough time to grow spinach to maturity outdoors.
The rule of thumb
Sow spinach 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 Portland's frost dates.
Confidence 89/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.