What to plant in August in Wisconsin
In Wisconsin (WI), August sits about 7 weeks before the average first fall frost (September 30). The state averages 143 frost-free days a year (last frost May 10, first frost September 30; USDA zones 3b, 4a, 4b, 5a, 5b).
22 crops have a sowing or planting window this month, including beet, cilantro / coriander, bok choy / pak choi, borage, dill, fava bean (broad bean) - and 12 of those windows close during August.
Dates here come from Wisconsin frost dates (last frost May 10, first frost Sep 30). For one crop in detail, see when to plant beet, lettuce or spinach in Wisconsin.
Wisconsin: planting activity through the year
Last chance in August
Beet (sow for a fall crop, by Aug 5) · Cilantro / Coriander (sow for a fall crop, by Aug 5) · Bok Choy / Pak Choi (sow for a fall crop, by Aug 12) · Borage (sow for a fall crop, by Aug 12) · Dill (sow for a fall crop, by Aug 12) · Fava Bean (Broad Bean) (sow for a fall crop, by Aug 12) · Green Onion / Scallion (sow for a fall crop, by Aug 12) · Kohlrabi (sow for a fall crop, by Aug 12) · Lettuce (sow for a fall crop, by Aug 12) · Mache (Corn Salad) (sow for a fall crop, by Aug 12) · Mizuna (sow for a fall crop, by Aug 12) · Rapini (Broccoli Raab) (sow for a fall crop, by Aug 12)
For fall and winter harvests (20)
Sowings counted back from Wisconsin'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 |
|---|---|---|---|
| Beet | Sow for a fall crop | Jul 19 – Aug 5 | Last chance - ends Aug 5 |
| Cilantro / Coriander | Sow for a fall crop | Jul 19 – Aug 5 | Last chance - ends Aug 5 |
| Bok Choy / Pak Choi | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Borage | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Dill | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Fava Bean (Broad Bean) | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Green Onion / Scallion | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Kohlrabi | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Lettuce | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Mache (Corn Salad) | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Mizuna | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Rapini (Broccoli Raab) | Sow for a fall crop | Jul 26 – Aug 12 | Last chance - ends Aug 12 |
| Chervil | Sow for a fall crop | Aug 2 – Aug 19 | Aug 2 – Aug 19 |
| Mustard Greens | Sow for a fall crop | Aug 2 – Aug 19 | Aug 2 – Aug 19 |
| Spinach | Sow for a fall crop | Aug 2 – Aug 19 | Aug 2 – Aug 19 |
| Tatsoi | Sow for a fall crop | Aug 2 – Aug 19 | Aug 2 – Aug 19 |
| Turnip | Sow for a fall crop | Aug 2 – Aug 19 | Aug 2 – Aug 19 |
| Arugula | Sow for a fall crop | Aug 9 – Aug 26 | Aug 9 – Aug 26 |
| Watercress | Sow for a fall crop | Aug 9 – Aug 26 | Aug 9 – Aug 26 |
| Radish | Sow for a fall crop | Aug 16 – Sep 2 | Opens Aug 16 |
Keep sowing (succession)
Repeat sowings of crops already in the ground, for a steady harvest instead of a glut.
- Basil: sow again on Aug 16
- Amaranth (Leaf): sow again on Aug 9
Harvesting in August
First harvests expected this month from crops sown or planted on time earlier in the season.
Planting dates for popular crops in Wisconsin
Every crop has its own full-year dates for Wisconsin: indoor start, transplant or direct sowing, and harvest.
Fall garden season: August garden jobs in Wisconsin
- The average first frost is September 30, about 7 weeks away. Pick tender crops (tomatoes, peppers, squash, beans) before it, or cover them on cold nights.
- Still time to sow or plant: beet, cilantro / coriander, bok choy / pak choi, borage, dill, fava bean (broad bean). 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 Wisconsin
Wisconsin spans USDA zones 3b, 4a, 4b, 5a, 5b. 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 Wisconsin in August?
22 crops have a window in August: beet, cilantro / coriander, bok choy / pak choi, borage, dill, fava bean (broad bean), green onion / scallion, kohlrabi, lettuce, mache (corn salad) and more. The tables above give the exact dates for each.
Is it too late to plant garlic in Wisconsin in August?
Not too late - it's actually a little early. In Wisconsin the next garlic window opens around October 11: plant in fall, after first frost.
Is it too late to plant tomatoes in Wisconsin in August?
For this year, yes - the tomato windows in Wisconsin have closed. The next step is to start seeds indoors from about March 15.
When is the first frost in Wisconsin?
The statewide average first fall frost is around September 30 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 Wisconsin in August?
From plantings made on time: radicchio, tarragon, potato, fennel (bulb), mint, lemon balm, cucumber, tomato, sweet corn, sweet marjoram.
What to plant in August in other states
Dates are computed from Wisconsin’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.