What to plant in September in Pennsylvania
In Pennsylvania (PA), September sits about 4 weeks before the average first fall frost (October 10). The state averages 162 frost-free days a year (last frost May 1, first frost October 10; USDA zones 5a, 5b, 6a, 6b, 7a, 7b).
3 crops have a sowing or planting window this month: arugula, watercress, radish - and 3 of those windows close during September.
Dates here come from Pennsylvania frost dates (last frost May 1, first frost Oct 10). For one crop in detail, see when to plant arugula, radish or tomato in Pennsylvania.
Pennsylvania covers a very wide range of climates, so dates near you can be two weeks or more either side of these. Enter your ZIP code in the planting calendar for dates tuned to your town.
Pennsylvania: planting activity through the year
Last chance in September
Arugula (sow for a fall crop, by Sep 5) · Watercress (sow for a fall crop, by Sep 5) · Radish (sow for a fall crop, by Sep 12)
For fall and winter harvests (3)
Sowings counted back from Pennsylvania's first fall frost, so the crop matures before the cold - or, for garlic and similar, planted after it.
| Crop | What to do | Window | This month |
|---|---|---|---|
| Arugula | Sow for a fall crop | Aug 19 – Sep 5 | Last chance - ends Sep 5 |
| Watercress | Sow for a fall crop | Aug 19 – Sep 5 | Last chance - ends Sep 5 |
| Radish | Sow for a fall crop | Aug 26 – Sep 12 | Last chance - ends Sep 12 |
Harvesting in September
First harvests expected this month from crops sown or planted on time earlier in the season.
Planting dates for popular crops in Pennsylvania
Every crop has its own full-year dates for Pennsylvania: indoor start, transplant or direct sowing, and harvest.
Spring bulbs to plant in September in Pennsylvania
Tulips, daffodils, hyacinths and crocus are planted in fall, once the soil has cooled and before it freezes. The exact window depends on the state, so our bulb guide quotes what each extension service says.
Fall garden season: September garden jobs in Pennsylvania
- The average first frost is October 10, about 4 weeks away. Pick tender crops (tomatoes, peppers, squash, beans) before it, or cover them on cold nights.
- Still time to sow or plant: arugula, watercress, radish. Fast greens and radishes are the safest bets this late.
- Row cover buys 4-6°F of frost protection and weeks of extra harvest - see season extension.
- Pull finished crops and sow a cover crop (cereal rye or crimson clover) into empty beds before the soil gets cold.
USDA zone chart for Pennsylvania
Pennsylvania spans USDA zones 5a, 5b, 6a, 6b, 7a, 7b. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average.
Questions gardeners ask
What vegetables can I plant in Pennsylvania in September?
3 crops have a window in September: arugula, watercress, radish. The tables above give the exact dates for each.
Is it too late to plant garlic in Pennsylvania in September?
Not too late - it's actually a little early. In Pennsylvania the next garlic window opens around October 21: plant in fall, after first frost.
Is it too late to plant tomatoes in Pennsylvania in September?
For this year, yes - the tomato windows in Pennsylvania have closed. The next step is to start seeds indoors from about March 6.
When is the first frost in Pennsylvania?
The statewide average first fall frost is around October 10 and the last spring frost around May 1. Pennsylvania covers a wide range of climates, so local dates can differ by two weeks or more - look yours up by ZIP code.
What can I harvest in Pennsylvania in September?
From plantings made on time: leek, parsnip, salsify, pumpkin, rosemary, celery, luffa (loofah gourd), peanut, sweet potato, zucchini / summer squash.
What to plant in September in other states
Dates are computed from Pennsylvania’s statewide average frost dates (from NOAA/NCEI climate normals) and each crop’s timing in our crop database. Your garden may be a week or two either side - for dates tuned to your ZIP code, use the planting calendar.