When to Plant Impatiens in Alton, IL

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

By checking out the USDA zone info for Alton it's possible to determine when you can plant impatiens.


Planting Calendar for Impatiens

Frost tolerance for impatiens: Not tolerant of frost.
When to plant: After the last frost.

Since impatiens do not do well in cold weather you have to wait until after all chance of frost has passed before you can plant them.

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

The earliest that you can plant impatiens in Alton 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 impatiens and expect a good harvest is probably August. Any later than that and your impatiens may not have a chance to fully mature. You can get started a little bit earlier by starting your impatiens indoors.

Last Frost Date

The average date of last frost is April 15 in Alton. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Alton is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Alton last frost occurs after April 15 be ready to cover your impatiens if you have a late frost.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-10°F
Highest Expected Low-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Alton

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