The best time to plant vegetables in Wisconsin depends on the specific vegetable and the local frost dates. Wisconsin has an average of about 110 frost-free days between the last spring frost and the first fall frost. The last frost dates vary by location, generally from mid-May to late May in most parts of the state, and the first frost dates occur in September. Generally:
- Cool-season vegetables like peas, lettuce, spinach, radishes, and greens can be planted before the last frost date in mid to late April.
- Warm-season vegetables like tomatoes, peppers, beans, cucumbers, and squash are best started indoors in early spring and transplanted after the last frost date in mid to late May.
- Direct sow warm-season crops like beans and corn starting in mid-May.
- Late-season planting can continue until early August for some crops to maximize the growing season.
For example, in Madison, Wisconsin (USDA Zone 5), the frost-free growing season typically starts around May 2. Seedlings of frost-tender plants like tomatoes and peppers are best transplanted outdoors in late May after the last frost. Cold-hardy plants can be started indoors in March-April and some seeds directly sown into the garden as early as mid-April.
In northern Wisconsin with a shorter growing season, starting seeds indoors around March to early April and planting out after the last frost date in late May is advised. Cold-hardy varieties can sometimes be directly sown earlier if conditions allow.
Summarized planting timing in Wisconsin:
Vegetable Type| Planting Timeframe
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Cool-season seeds| Mid-April to early May
Warm-season transplants| After last frost (mid to late May)
Warm-season direct sow| Mid-May onward
Late-season planting| Until early August
Knowing the local frost dates and starting seeds indoors accordingly helps optimize vegetable planting in Wisconsin.
