When to plant onion in Newark
Onion is cold-hardy, so every date keys off Newark's frost dates of Apr 3.
Step 1 · Sow
Start seeds indoors
Jan 23 – Feb 13
Before your last frost, on a warm windowsill or heat mat.
Step 2 · Plant
Transplant outdoors
Apr 19 – May 10
Once frost risk has passed and nights stay mild.
Step 3 · Harvest
Harvest window
Jul 18 – Aug 7
Picking runs until conditions turn against the crop.
Window
Days to maturity
90 – 110 d
Newark's 223-day season leaves this much room.
Onion on Newark'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 3
NOV 11
Common questions
When will onion be ready to harvest in Newark?
Expect to harvest from around mid July (Jul 18–Aug 7) in Newark, based on its local frost dates. Confidence 77%.
When should I start onion seeds indoors in Newark?
Start seeds indoors around late January (Jan 23–Feb 13) in Newark, based on its local frost dates. Confidence 82%.
When can I transplant onion outdoors in Newark?
Transplant outdoors around mid April (Apr 19–May 10) in Newark, based on its local frost dates. Confidence 83%.
How long is the growing season in Newark?
Newark has roughly 223 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 Newark's frost dates.
Confidence 86/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.