When to Plant Spearmint in Decatur, IL

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.

By looking at the USDA zone info for Decatur you should be able to determine when it's a good idea to plant spearmint.


Planting Calendar for Spearmint

Frost tolerance for spearmint: Very tolerant of frost.
When to plant: Up to 7 weeks before last frost.

You can plant spearmint earlier in the year because they are very cold tolerant.

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

The earliest that you can plant spearmint in Decatur is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant spearmint and expect a good harvest is probably September. You probably don't want to wait any later than that or else your spearmint may not have a chance to really do well. You can get started a few weeks earlier by starting your spearmint indoors.

Last Frost Date

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

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Decatur and it changes from year to year. Half of the time in Decatur last frost occurs after April 15 so just be sure to be ready to protect your spearmint in the event of a late frost.

USDA Zone Info for Decatur

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 Decatur

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