What to plant in September in South Dakota
In South Dakota (SD), September sits about 1 week before the average first fall frost (September 25). The state averages 138 frost-free days a year (last frost May 10, first frost September 25; USDA zones 3b, 4a, 4b, 5a).
1 crop has a sowing or planting window this month: shallot.
Dates here come from South Dakota frost dates (last frost May 10, first frost Sep 25). For one crop in detail, see when to plant tomato, lettuce or garlic in South Dakota.
South Dakota: planting activity through the year
For fall and winter harvests (1)
Sowings counted back from South Dakota'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 |
|---|---|---|---|
| Shallot | Plant in fall (after first frost) | Sep 29 – Oct 16 | Opens Sep 29 |
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 South Dakota
Every crop has its own full-year dates for South Dakota: indoor start, transplant or direct sowing, and harvest.
Spring bulbs to plant in September in South Dakota
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 South Dakota
- The average first frost is September 25, about 1 weeks away. Pick tender crops (tomatoes, peppers, squash, beans) before it, or cover them on cold nights.
- Still time to sow or plant: shallot. 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 South Dakota
South Dakota spans USDA zones 3b, 4a, 4b, 5a. 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 South Dakota in September?
1 crops have a window in September: shallot. The tables above give the exact dates for each.
Is it too late to plant garlic in South Dakota in September?
Not too late - it's actually a little early. In South Dakota the next garlic window opens around October 6: plant in fall, after first frost.
Is it too late to plant tomatoes in South Dakota in September?
For this year, yes - the tomato windows in South Dakota have closed. The next step is to start seeds indoors from about March 15.
When is the first frost in South Dakota?
The statewide average first fall frost is around September 25 and the last spring frost around May 10. Your town can be a week or two either side - look yours up by ZIP code.
What can I harvest in South Dakota in September?
From plantings made on time: chili pepper, watermelon, leek, winter squash, zucchini / summer squash, parsnip, cucumber, salsify, pumpkin, broccoli.
What to plant in September in other states
Dates are computed from South Dakota’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.