When to Plant Dahlias in Mount Prospect, IL

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

A way of making a decision about when it's possible to plant dahlias is to use the USDA zone info for Mount Prospect.


Planting Calendar for Dahlias

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

Dahlias require warm weather which means that it's important to wait until it warms up after the last frost before you can plant them.

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

The earliest that you can plant dahlias in Mount Prospect 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 dahlias and expect a good harvest is probably August. If you wait any later than that and your dahlias may not have a chance to really do well. You can get started a couple of weeks earlier by starting your dahlias indoors.

Last Frost Date

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

Just be sure to remember that USDA zone info for Mount Prospect may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Mount Prospect there is a last frost after April 15 so be sure to be ready to protect your dahlias if you have a late frost.

USDA Zone Info for Mount Prospect

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 Mount Prospect

You may be interested in your other planting guides for Mount Prospect.