When to plant onion in Manchester
Onion is cold-hardy, so every date keys off Manchester's frost dates of Apr 25.
Step 1 · Sow
Start seeds indoors
Feb 14 – Mar 7
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 4 – Apr 25
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 3 – Jul 23
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Manchester's 183-day season leaves this much room.
Onion on Manchester'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 25
OCT 25
Common questions
When will onion be ready to harvest in Manchester?
Expect to harvest from around early July (Jul 3–Jul 23) in Manchester, based on its local frost dates. Confidence 76%.
When should I start onion seeds indoors in Manchester?
Start seeds indoors around mid February (Feb 14–Mar 7) in Manchester, based on its local frost dates. Confidence 80%.
When can I transplant onion outdoors in Manchester?
Transplant outdoors around early April (Apr 4–Apr 25) in Manchester, based on its local frost dates. Confidence 84%.
How long is the growing season in Manchester?
Manchester has roughly 183 frost-free days, which is enough time to grow onion to maturity outdoors.
The rule of thumb
Sow onion 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 Manchester's frost dates.
Confidence 84/100 · NOAA GHCN-Daily · 1991–2020 normals · frost dates are probabilities, not guarantees.