Green bean · Philadelphia, Pennsylvania, United States
When to plant green beans in Philadelphia
Main outdoor window
21 Apr - 5 May
The window this page is built around.
Timed from last spring frost
14 April
In Philadelphia, on your chosen risk.
Ready to pick
10-20 Jun
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Philadelphia
Each window is a range, not a single day. Earlier in the range buys you a longer season; later in it buys you a safer one.
Sow direct
21 Apr - 5 May
One week after your last frost.
Harvest
10-20 Jun
Green beans through the year
Against the frost risk in Philadelphia
Why these dates
Sow a short row every two weeks from one week after last frost until ten weeks before first frost. Beans crop heavily for a fortnight then decline, so succession matters more than quantity.
Beans are killed by the lightest frost at any stage. They also germinate poorly below 15C, so patience in spring pays.
Seed packets and extension guides express timing as weeks either side of the last spring frost, because that is the only reference point that travels. Green beans are timed for direct sowing 1 weeks after it, and this page simply resolves those offsets against the frost date computed for Philadelphia.
The median frost-free season here is 202 days, against 50 to 60 days to maturity for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Philadelphia
Other vegetables to time
Growing green beans in Philadelphia
When should I plant green beans in Philadelphia?
Aim for 21 Apr - 5 May in an average year. If you would rather not gamble on the weather, wait until 30 Apr - 14 May - by then frost has finished in nine years out of ten.
When will green beans be ready to harvest in Philadelphia?
Expect to start picking around 10-20 Jun, based on 50 to 60 days to maturity from the planting date calculated for this location.
How much frost will green beans tolerate?
Beans are killed by the lightest frost at any stage. They also germinate poorly below 15C, so patience in spring pays.