When to Plant Sunflowers in Osceola, IA

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant sunflowers in Osceola should be figured out by using the USDA zone info.


Planting Calendar for Sunflowers

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

Since sunflowers require warm weather you really should wait until after the last frost 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 Osceola 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 really do well. If you are starting your sunflowers indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Osceola. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Osceola is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Osceola you get surprised by a frost after April 15 be ready to cover your sunflowers if you have a surprise late frost.

USDA Zone Info for Osceola

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 Osceola

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