When to plant radish in Philadelphia
Radish is cold-hardy, so every date keys off Philadelphia's frost dates of Mar 28.
Step 1 · Sow
Direct sow outdoors
Mar 3 – Mar 24
Sow straight into warm, workable soil.
Step 2 · Harvest
Harvest window
Mar 28 – Apr 2
Picking runs until conditions turn against the crop.
Step 3 · Second sowing
Autumn / second sowing
Oct 2 – Oct 16
A second window for a fall crop, timed to mature before the first frost.
Step 4 · Second harvest
Autumn crop harvest
Nov 3 – Nov 8
Maturity window for the second sowing.
Window
Days to maturity
25 – 30 d
Philadelphia's 234-day season leaves this much room.
Radish on Philadelphia'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
MAR 28
NOV 22
Common questions
When can I sow radish outdoors in Philadelphia?
Direct-sow around early March (Mar 3–Mar 24) in Philadelphia, based on its local frost dates. Confidence 84%.
When will radish be ready to harvest in Philadelphia?
Expect to harvest from around late March (Mar 28–Apr 2) in Philadelphia, based on its local frost dates. Confidence 78%.
Can I plant radish in autumn in Philadelphia?
Yes — Philadelphia supports a second, autumn sowing of radish around early October (Oct 2–Oct 16), timed to mature before the first fall frost.
How long is the growing season in Philadelphia?
Philadelphia has roughly 234 frost-free days, which is enough time to grow radish to maturity outdoors.
The rule of thumb
Sow radish 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 Philadelphia's frost dates.
Confidence 87/100 · Curated · based on NOAA GHCN-Daily 1991–2020 normal · frost dates are probabilities, not guarantees.