When can I plant Sunflowers in Lisle, IL

The USDA Zone info is a great tool for gardeners to help us figure out our gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for our area.

The earliest that you can plant sunflowers in Lisle can be estimated by looking at the USDA zone info.


Planting Calendar for Sunflowers

Frost tolerance for sunflowers: Not tolerant of frost.
When you should plant them: After the last frost.

Since sunflowers do not do well in cold weather it's necessary to wait until after the last frost has passed before you can plant them.

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 Lisle 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. If you wait any later than that and your sunflowers may not have a chance to grow to maturity. Starting your sunflowers indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Lisle. It might get as low as -15°F during the coldest months of winter.

Keep in mind that our actual date of last frost is just an average because it is based on the USDA zone info for Lisle and it will vary from year to year. Since half of the time in Lisle there is a last frost after April 15 be ready to cover your sunflowers in the event of a surprise late frost.

USDA Zone Info for Lisle

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 Lisle

You may be interested in our other planting guides for Lisle.