When to Plant Sunflowers in Grafton, WI

One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Grafton can be read to estimate when you can plant sunflowers.

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Planting Calendar for Sunflowers

Frost tolerance for sunflowers: Not tolerant of frost.
When to plant: After the last frost when the weather gets warmer.

You should not plant sunflowers until after the last frost because they do not do well in cold weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant sunflowers
Possibly ok, but a risky time to plant sunflowers
Probably not a good time to plant sunflowers

The earliest that you can plant sunflowers in Grafton is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sunflowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sunflowers may not have a chance to really do well. Starting your sunflowers indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Grafton. It might get as low as -15°F during the coldest months of winter.

Keep in mind that USDA zone info for Grafton is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Grafton last frost occurs after April 15 be ready to cover your sunflowers in the event of a surprise late frost.

USDA Zone Info for Grafton

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-15°F
Highest Expected Low-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Grafton

You may be interested in your other planting guides for Grafton.