When to plant · 16 cities · zones 4b–6a
When to plant basil in Wisconsin
Start Genovese Basil seeds indoors around Apr 6 and transplant around May 18 — the Wisconsin statewide median, counted from a last spring frost of May 4 across 779 ZIP codes and 202 NOAA stations.
The rule: Basil is damaged below about 50 °F, well before frost: transplant two weeks after the last frost, not on it.
Wisconsin basil, by step
Statewide median last frost May 4, first fall frost Oct 7, 2027 season. Each cultivar's own indoor lead time and days to maturity, same engine as the Plan Builder.
| Cultivar | Start indoors | Plant out | First harvest | Days |
|---|---|---|---|---|
| Genovese BasilGenovese | Apr 6 | May 18 | Jul 17 | 60 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost. Statewide dates are the ZIP-weighted median of every NOAA 1991–2020 station Wisconsin's ZIP codes resolve to; 4 of 783 ZIPs have no datable freeze and are left out.
Basil in Wisconsin, city by city
Genovese Basil, scheduled from each city's nearest NOAA station — the same dates as its frost page.
| City | Last frost | Start indoors | Plant out | First harvest |
|---|---|---|---|---|
| Milwaukeezone 6a | Apr 26 | Mar 29 | May 10 | Jul 9 |
| Madisonzone 5a | May 1 | Apr 3 | May 15 | Jul 14 |
| Green Bayzone 5b | May 7 | Apr 9 | May 21 | Jul 20 |
| Kenoshazone 5b | Apr 28 | Mar 31 | May 12 | Jul 11 |
| Racinezone 6a | Apr 24 | Mar 27 | May 8 | Jul 7 |
| Appletonzone 5b | May 4 | Apr 6 | May 18 | Jul 17 |
| Eau Clairezone 4b | May 8 | Apr 10 | May 22 | Jul 21 |
| Waukeshazone 5b | Apr 30 | Apr 2 | May 14 | Jul 13 |
| Oshkoshzone 5b | Apr 24 | Mar 27 | May 8 | Jul 7 |
| Janesvillezone 5b | Apr 26 | Mar 29 | May 10 | Jul 9 |
| West Alliszone 5b | Apr 26 | Mar 29 | May 10 | Jul 9 |
| La Crossezone 5a | Apr 23 | Mar 26 | May 7 | Jul 6 |
| Sheboyganzone 6a | May 2 | Apr 4 | May 16 | Jul 15 |
| Wauwatosazone 5b | Apr 26 | Mar 29 | May 10 | Jul 9 |
| Fond du Laczone 5b | May 1 | Apr 3 | May 15 | Jul 14 |
| Brookfieldzone 5b | Apr 26 | Mar 29 | May 10 | Jul 9 |
What these basil become
What Wisconsin basil need
Genovese Sweet Basil Seed
The large-leaf, low-anise Italian basil that pesto is defined by. Thai and lemon basils are good plants and wrong ingredients.
Organic Seed Starter Potting MixMust have
Seed-starting mix is not potting soil with a nicer label — it is finer, lighter, and low in nutrients on purpose, because a seedling's first roots want air and moisture, not fertiliser.
T8 Full-Spectrum Grow Lights, 1 ft 4-packMust have
A south window in March delivers a fraction of the light a pepper seedling needs, and the plant tells you by stretching. Two inches of LED above the canopy for 16 hours a day fixes it permanently.
5-Gallon Fabric Grow Bags, 5-Pack
Fabric pots air-prune roots and drain faster than a plastic pot can, which is the entire reason container tomatoes fail. Five gallons is the honest minimum for a pepper; a tomato wants ten.
Ocean Forest Potting SoilMust have
Pre-charged with enough nutrition to carry a transplant for its first month without feeding, which is exactly the window when most container plants stall.
6" Micro-Tip Pruning SnipsMust have
Ninety percent of sauce-garden cutting is snipping a pepper stem or a basil node, and a fine-tipped snip does it better than any pruner. Pulling peppers by hand tears the branch.
Mesh Strainers, Stainless, 3-Count
The last pass before bottling. A fine mesh catches the skin fragments and seed shards that make a hot sauce gritty and clog a woozy bottle's dripper insert.
Paid links. We earn a commission from Amazon if you buy; you pay the same. Disclosure.
Basil in Wisconsin: questions
When should I plant basil in Wisconsin?
Transplant around May 18 at the statewide median; across the state that date runs from May 10 in the warmest tenth of Wisconsin's ZIP codes to Jun 2 in the coldest. To cut the freeze risk to one year in ten, count from May 20 instead of the median last frost. Use the city table for your own town.
When do I start basil seeds indoors in Wisconsin?
Around Apr 6 for Genovese Basil: 4 weeks before the statewide median last frost, on soil held at 70–80 °F.
When is the last frost in Wisconsin?
The ZIP-weighted median of NOAA 1991–2020 station medians is May 4. In the warmest tenth of Wisconsin's ZIP codes the median last frost falls on or before Apr 26; in the coldest tenth, on or after May 19.
When will Wisconsin basil be ready to harvest?
Genovese Basil planted on the statewide date is ready around Jul 17: 60 days from transplant.
More for Wisconsin
- When to plant tomatoes
- When to plant peppers
- When to plant tomatillos
- When to plant onions
- When to plant cilantro
- When to plant carrots
- When to plant mustard greens
Basil in every state → · Wisconsin frost dates → · How frost-date math works →