When to Plant in Wisconsin: Vegetable & Flower Planting Calendar
Quick answer
Plant around your local last spring frost: across the 783 Wisconsin ZIP codes where frost comes in most years, the median is May 4 and the median first fall frost is Oct 7 (nearest NOAA station, 1991–2020). Transplant tomatoes 1–2 weeks after your last frost: Zone 4 areas: May 17 – May 24; Zone 5 areas: May 8 – May 15.
Wisconsin spans USDA hardiness zones 4a–6a on the 2023 USDA map (by ZIP code, via PRISM). For the 783 of its 783 ZIP codes where frost comes in most years, the nearest NOAA station’s median last spring frost (32°F, 1991–2020) is May 4 (middle 80% of ZIP codes: Apr 26 – May 19) and the median first fall frost is Oct 7 (Sep 28 – Oct 18). Use this guide to time seed-starting, transplanting and fall planting.
Where these dates come from: every date range is counted from the median (50% probability) 32°F last spring and first fall frost dates in NOAA’s 1991–2020 U.S. Climate Normals for the area shown. The rule under each date, such as “4–6 weeks before last frost,” shows how it was counted. These are averages: in about half of years a frost still comes after the spring date, and elevation, nearby water and microclimate can shift your yard by a week or more. For dates for your exact location, enter your ZIP code in the planner.
How we count planting dates: the weeks before or after frost for each crop come from university extension planting guides: UNH Extension, When to Plant Your Vegetable Garden; Rutgers FS787, Starting Vegetable Seeds Indoors; Virginia Tech 426-331, Home Garden Vegetable Planting Guide; University of Maryland Extension, Vegetable Planting Calendar; and University of Idaho CIS 1209 (marigolds and zinnias). Bulb windows approximate Rutgers’ rule to plant when soil falls below 60°F (FS1220), and garlic follows SDSU, Illinois and Virginia Tech. Temperature notes: UMD (potatoes), UMN (sweet corn), UC ANR (peppers, hardening off), UMN (eggplant), Colorado State (tomatoes) and SDSU (hardening off).
Wisconsin frost dates by zone area
| Zone areas | Most common nearest NOAA stations | Median last spring frost (32°F) | Median first fall frost (32°F) |
|---|---|---|---|
| Zone 4 (297 ZIP codes) | Blair, WI, Baldwin, WI, Antigo, WI | May 10middle 80%: May 5 – May 24 | Oct 1middle 80%: Sep 24 – Oct 5 |
| Zone 5 (448 ZIP codes) | Appleton, WI, Dodgeville Wwtp, WI, Mt Mary College, WI | May 1middle 80%: Apr 26 – May 8 | Oct 10middle 80%: Oct 4 – Oct 18 |
Source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991–2020, annual/seasonal freeze-date probabilities (32°F, 50% probability). Station-level medians; your yard may differ.
How this table is built: each Wisconsin ZIP code is matched to its nearest NOAA 1991–2020 freeze-data station (within 60 miles) and grouped by its 2023 USDA hardiness zone; dates are medians across the ZIP codes in each group. Zone groups with fewer than 5% of ZIP codes (33 ZIP codes) are left out of the columns. Some nearest stations are across the state line (Antioch, IL, Dubuque L&D 11, IA, Galena, IL, Guttenberg L&D 10, IA, Hastings Dam 2, MN, Iron Mtn-Kingsford Wwtp, MI…). For your own ZIP, use the planner.
Wisconsin vegetable planting calendar
Planting dates for each zone area of Wisconsin, counted from that area’s median frost dates (shown under each column). Rows run in calendar order. For your exact dates, enter your ZIP.
| Plant, task and rule | Zone 4 areasLast frost May 10 · First frost Oct 1 | Zone 5 areasLast frost May 1 · First frost Oct 10 |
|---|---|---|
| Broccoli · Start indoors8–10 weeks before last frost | Mar 1 – Mar 15 | Feb 20 – Mar 6 |
| Cabbage · Start indoors8–10 weeks before last frost | Mar 1 – Mar 15 | Feb 20 – Mar 6 |
| Kale · Start indoors8–10 weeks before last frost | Mar 1 – Mar 15 | Feb 20 – Mar 6 |
| Tomatoes · Start indoors6–8 weeks before last frost | Mar 15 – Mar 29 | Mar 6 – Mar 20 |
| Peppers · Start indoors6–8 weeks before last frost | Mar 15 – Mar 29 | Mar 6 – Mar 20 |
| Eggplant · Start indoors6–8 weeks before last frost | Mar 15 – Mar 29 | Mar 6 – Mar 20 |
| Peas · Direct sow4–6 weeks before last frost | Mar 29 – Apr 12Harvest (est.) May 28 – Jul 1 | Mar 20 – Apr 3Harvest (est.) May 19 – Jun 22 |
| Spinach · Direct sow4–6 weeks before last frost | Mar 29 – Apr 12Harvest (est.) May 13 – Jun 11 | Mar 20 – Apr 3Harvest (est.) May 4 – Jun 2 |
| Basil · Start indoors4–6 weeks before last frost | Mar 29 – Apr 12 | Mar 20 – Apr 3 |
| Radishes · Direct sow2–5 weeks before last frost | Apr 5 – Apr 26Harvest (est.) Apr 25 – May 26 | Mar 27 – Apr 17Harvest (est.) Apr 16 – May 17 |
| Lettuce · Direct sow2–4 weeks before last frost | Apr 12 – Apr 26Harvest (est.) Jun 11 – Jul 15 | Apr 3 – Apr 17Harvest (est.) Jun 2 – Jul 6 |
| Onions (sets/transplants) · Plant sets/transplants2–4 weeks before last frost | Apr 12 – Apr 26Harvest (est.) Jul 6 – Aug 24 | Apr 3 – Apr 17Harvest (est.) Jun 27 – Aug 15 |
| Broccoli · Transplant2–4 weeks before last frost | Apr 12 – Apr 26Harvest (est.) Jun 1 – Jul 5 | Apr 3 – Apr 17Harvest (est.) May 23 – Jun 26 |
| Cabbage · Transplant2–4 weeks before last frost | Apr 12 – Apr 26Harvest (est.) Jun 21 – Jul 25 | Apr 3 – Apr 17Harvest (est.) Jun 12 – Jul 16 |
| Kale · Transplant2–4 weeks before last frost | Apr 12 – Apr 26 | Apr 3 – Apr 17 |
| Marigolds · Start indoors0–3 weeks before last frost (3–4 weeks before setting out; Univ. of Idaho) | Apr 19 – May 10 | Apr 10 – May 1 |
| Zinnias · Start indoors0–3 weeks before last frost (3–4 weeks before setting out; Univ. of Idaho) | Apr 19 – May 10 | Apr 10 – May 1 |
| Potatoes · Plant seed potatoes1–2 weeks before last frost | Apr 26 – May 3Harvest (est.) Jul 20 – Aug 21 | Apr 17 – Apr 24Harvest (est.) Jul 11 – Aug 12 |
| Marigolds · Direct sow / transplantfrom the last frost to 2 weeks after (Univ. of Idaho) | May 10 – May 24 | May 1 – May 15 |
| Zinnias · Direct sow / transplantfrom the last frost to 2 weeks after (Univ. of Idaho) | May 10 – May 24 | May 1 – May 15 |
| Tomatoes · Transplant1–2 weeks after last frost | May 17 – May 24Harvest (est.) Jul 26 – Aug 22 | May 8 – May 15Harvest (est.) Jul 17 – Aug 13 |
| Beans (bush & pole) · Direct sow1–2 weeks after last frost | May 17 – May 24Harvest (est.) Jul 1 – Aug 2 | May 8 – May 15Harvest (est.) Jun 22 – Jul 24 |
| Sweet corn · Direct sow1–2 weeks after last frost | May 17 – May 24Harvest (est.) Jul 21 – Aug 22 | May 8 – May 15Harvest (est.) Jul 12 – Aug 13 |
| Cucumbers · Direct sow1–2 weeks after last frost | May 17 – May 24Harvest (est.) Jun 26 – Jul 28 | May 8 – May 15Harvest (est.) Jun 17 – Jul 19 |
| Squash · Direct sow1–2 weeks after last frost | May 17 – May 24Harvest (est.) Jun 26 – Jul 13 | May 8 – May 15Harvest (est.) Jun 17 – Jul 4 |
| Pumpkins · Direct sow1–3 weeks after last frost | May 17 – May 31Harvest (est.) Aug 5 – Sep 8 | May 8 – May 22Harvest (est.) Jul 27 – Aug 30 |
| Basil · Transplant1–2 weeks after last frost | May 17 – May 24Harvest (est.) Jun 28 – Jul 5 | May 8 – May 15Harvest (est.) Jun 19 – Jun 26 |
| Peppers · Transplant2–3 weeks after last frost | May 24 – May 31Harvest (est.) Jul 28 – Aug 14 | May 15 – May 22Harvest (est.) Jul 19 – Aug 5 |
| Eggplant · Transplant2–3 weeks after last frost | May 24 – May 31Harvest (est.) Aug 2 – Aug 29 | May 15 – May 22Harvest (est.) Jul 24 – Aug 20 |
| Broccoli · Fall transplant10–12 weeks before first fall frost | Jul 9 – Jul 23Harvest (est.) Aug 28 – Oct 1 | Jul 18 – Aug 1Harvest (est.) Sep 6 – Oct 10 |
| Cabbage · Fall transplant10–12 weeks before first fall frost | Jul 9 – Jul 23Harvest (est.) Sep 17 – Oct 21 | Jul 18 – Aug 1Harvest (est.) Sep 26 – Oct 30 |
| Kale · Fall sow8–10 weeks before first fall frost | Jul 23 – Aug 6Harvest (est.) Sep 11 – Oct 15 | Aug 1 – Aug 15Harvest (est.) Sep 20 – Oct 24 |
| Lettuce · Fall sow6–8 weeks before first fall frost | Aug 6 – Aug 20Harvest (est.) Oct 5 – Nov 8 | Aug 15 – Aug 29Harvest (est.) Oct 14 – Nov 17 |
| Spinach · Fall sow4–7 weeks before first fall frost (Virginia Tech) | Aug 13 – Sep 3Harvest (est.) Sep 27 – Nov 2 | Aug 22 – Sep 12Harvest (est.) Oct 6 – Nov 11 |
| Radishes · Fall sow4–6 weeks before first fall frost | Aug 20 – Sep 3Harvest (est.) Sep 9 – Oct 3 | Aug 29 – Sep 12Harvest (est.) Sep 18 – Oct 12 |
| Daffodils · Fall plant bulbs4 weeks before to 2 weeks after first fall frost (our approximation of when soil falls below 60°F; Rutgers) | Sep 3 – Oct 15 | Sep 12 – Oct 24 |
| Tulips · Fall plant bulbs2 weeks before to 4 weeks after first fall frost (our approximation of when soil falls below 60°F; Rutgers) | Sep 17 – Oct 29 | Sep 26 – Nov 7 |
| Garlic · Fall plant cloves2 weeks before to 3 weeks after first fall frost, while the soil is still workable (SDSU, Illinois, Virginia Tech) | Sep 17 – Oct 22Harvest (est.) May 25, 2027 – Jul 19, 2027 | Sep 26 – Oct 31Harvest (est.) Jun 3, 2027 – Jul 28, 2027 |
About the harvest estimates
Each expected harvest window adds the days to harvest from the sources below to the planting window. Days count from sowing seed (or planting seed potatoes, onion sets or garlic cloves) or, where marked, from setting transplants out; “Start indoors” rows have no harvest of their own. Harvest timing varies with variety and weather, and many crops keep producing for weeks after the first picking. For frost-tender crops (tomatoes, peppers, eggplant, beans, sweet corn, cucumbers, squash, pumpkins, basil) the window stops at the first fall frost: harvest may end early at the first fall frost. Flowers and bulbs show no harvest window, and kale has no sourced figure for spring transplants.
Sources: UF/IFAS Extension, Florida Vegetable Gardening Guide (SP103/VH021), Table 1, “Days to Harvest”; University of Maryland Extension, Growing Onions in a Home Garden; University of Maryland Extension, Growing Garlic in a Home Garden; University of Maryland Extension, Growing Basil in a Home Garden.
Growing notes for each crop
- Peas: Tolerates light frost; sow when soil is workable
- Spinach: Fall crop too: sow 4–7 weeks before first fall frost (Virginia Tech)
- Lettuce: Bolts in heat; succession sow; fall crop too
- Radishes: Fast (3–4 weeks); sow again for fall (see Fall sow dates)
- Kale: Fall crop too (see Fall sow dates); frost sweetens leaves
- Onions (sets/transplants): Choose day-length type suited to your latitude
- Potatoes: Soil at least 45°F (UMD); hill as plants grow
- Broccoli: Cool-season; harden off; good fall crop
- Cabbage: Cool-season; harden off; good fall crop
- Tomatoes: Wait for nights reliably above about 52°F (Colorado State)
- Peppers: Need warm soil: about 65°F is optimal for transplanting (UC ANR)
- Eggplant: Transplant after nights stay above 50°F (UMN)
- Beans (bush & pole): Seeds rot in cold, wet soil
- Sweet corn: Soil 60°F+ (UNH, UMN); plant in blocks for pollination
- Cucumbers: Frost-tender; watch for cucumber beetles
- Squash: Frost-tender; watch for squash vine borer
- Pumpkins: For October pumpkins, many sow in late May–June
- Basil: Very cold-sensitive
- Marigolds: Easy warm-season annual
- Zinnias: Easy warm-season annual
- Tulips: Our frost-date window is an approximation of that soil rule. In zone 9, chill bulbs 12–16 weeks first (Clemson)
- Daffodils: Our frost-date window is an approximation of that soil rule; slightly earlier than tulips is fine
- Garlic: Harvest the following early summer
Wisconsin USDA zone guides: Zone 4 planting guide Zone 5 planting guide Zone 6 planting guide
How we count planting dates: the weeks before or after frost for each crop come from university extension planting guides: UNH Extension, When to Plant Your Vegetable Garden; Rutgers FS787, Starting Vegetable Seeds Indoors; Virginia Tech 426-331, Home Garden Vegetable Planting Guide; University of Maryland Extension, Vegetable Planting Calendar; and University of Idaho CIS 1209 (marigolds and zinnias). Bulb windows approximate Rutgers’ rule to plant when soil falls below 60°F (FS1220), and garlic follows SDSU, Illinois and Virginia Tech. Temperature notes: UMD (potatoes), UMN (sweet corn), UC ANR (peppers, hardening off), UMN (eggplant), Colorado State (tomatoes) and SDSU (hardening off).
Tips for Wisconsin gardeners
- Watch soil temperature, not just the calendar — warm-season crops stall in cold soil. An inexpensive soil thermometer helps.
- Harden off transplants over 7–10 days before planting out (UC ANR, SDSU).
- Ask your local Cooperative Extension office about varieties and timing for your county; find it in the USDA NIFA land-grant university directory.
- Keep weeds down early — see our weed identification guide.
Frequently asked questions
When is the last frost in Wisconsin?
Across the 783 Wisconsin ZIP codes where frost comes in most years, the median last spring frost (32°F, NOAA 1991–2020) at the nearest station is May 4, and the middle 80% of ZIP codes range from Apr 26 to May 19. Check the average for your ZIP code, and remember frost can occur after the average date.
When can I plant tomatoes in Wisconsin?
Transplant tomatoes outdoors 1–2 weeks after your average last frost, once nights stay above about 52°F (Colorado State). Typical dates: Zone 4 areas: May 17 – May 24; Zone 5 areas: May 8 – May 15.
What USDA zone is Wisconsin?
Wisconsin spans roughly USDA hardiness zones 4a–6a on the 2023 USDA map (by ZIP code, via PRISM). Hardiness zones describe winter low temperatures, not frost dates.
Other state planting calendars
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