When to Plant Potatoes in Green Bay, WI
Published: April 24, 2026
Potato Planting Dates for Green Bay, WI
| Start seeds indoors | Year-round |
| Last frost (average) | April 15 |
| Direct sow outdoors | March 25–April 4 |
| Minimum soil temperature | 45°F |
| Expect first harvest | June 3 – July 23 |
| First fall frost (average) | October 15 |
⚠ Plant seed potatoes 2–4 weeks before last frost when soil is workable and above 45°F. Hill soil up around stems as plants grow. Needs well-drained, loose soil.
Best Potato Varieties for Green Bay, WI
Consult a Green Bay-area nursery or your state extension office for potato varieties proven in Zone 5a.
Growing Potatoes in Green Bay
Green Bay sits in Zone 5a, with an average last frost of April 15 and first fall frost around October 15 — giving a 183-day frost-free growing season. Cool-season crops like potato benefit from Green Bay's cooler spring and fall windows, when temperatures stay in the 55–75°F sweet spot that produces the best flavor and least bolting.
Green Bay's cooler summers are close to ideal for potato. The same conditions that limit tomato and pepper yields benefit cool-season crops — slower bolting, sweeter flavor, and longer harvest windows. The fall potato crop in Green Bay is often more productive than the spring crop.
Green Bay's clay-loam soils are productive but benefit from annual compost amendment — 2 to 3 inches worked in before planting improves drainage and nutrient availability for potato. Consistent watering (1.5 inches per week) paired with organic mulch maintains the even moisture that clay-loam holds well. Avoid working wet soil in spring, which causes severe compaction in clay-loam blends.
Potato Calendar for Green Bay
| Month | Task |
|---|---|
| Year | Start seeds indoors under grow lights |
| April | Last frost — soil warming, prepare bed |
| March | Direct sow seeds into warm soil |
| June | Expect first harvest window to open |
| October | First fall frost — harvest remaining, end of outdoor season |
Potato Tips for Green Bay Gardeners
- •Cut seed potatoes into 2-inch chunks with at least two eyes each, then let cut surfaces heal for 24–48 hours before planting.
- •Plant 4 inches deep and 12 inches apart in loose, well-drained soil; add compost but avoid fresh manure.
- •Fall plantings in Green Bay often out-produce spring plantings — cooler temperatures slow bolting and concentrate flavor. Light frost can actually improve the taste of potato.
Common Potato Pests in Green Bay
- •Colorado Potato Beetle — peaks July in Zone 5a (active June–August); monitor closely during peak season and treat early.
- •Wireworm — peaks July in Zone 5a (active June–August); orange-brown beetle larvae in soil; trap with cut potato pieces buried in soil.
- •Potato Scab — peaks July in Zone 5a (active June–August); monitor closely during peak season and treat early.
Check plants every 2–3 days during peak season — early intervention prevents most infestations from becoming serious.
What to Plant with Potatoes in Green Bay
In Green Bay's cold climate, Bean and Corn are the most beneficial plants to grow alongside potato. Bean improves nearby plant health and pest resistance. Keep potato away from Tomato — it competes for nutrients or shares pest pressure. In short-season gardens, interplanting companions at transplant time maximizes each bed's productive weeks.
Frequently Asked Questions
When should I plant potato in Green Bay, WI?
In Green Bay (Zone 5a), direct sow potato around March 25–April 4. Soil must be at 45°F or warmer at 2-inch depth before sowing — cold soil rots the seeds.
What zone is Green Bay, WI for potato growing?
Green Bay is USDA Zone 5a. For potato, this means a frost-free growing season of roughly 26 weeks running from April 15 to October 15. Cool-season crops like potato thrive in this zone with both spring and fall planting windows available.
When is potato harvest season in Green Bay?
Expect the first potato harvest in Green Bay around June 3, with harvest continuing through July 23. This is based on 70–120 days from transplant or direct sow.
How long does it take to grow potato in Green Bay, WI?
From transplant or direct sow to first harvest, potato takes 70–120 days in Green Bay's climate. Based on a typical planting date of March 25–April 4, expect your first harvest around June 3. Green Bay's cooler Zone 5a climate often lands at the slower end of this range — cooler nights slow fruit development.
What soil does potato need in Green Bay?
Green Bay's clay-loam soil is productive for potato but benefits from annual compost amendment. Work 2–3 inches of compost into the top 10 inches before planting. Avoid working wet soil in spring — clay-loam compacts badly when wet. Consistent watering paired with organic mulch maintains the even moisture these soils hold well.