Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant mimulus in Zone 4a should be figured out by looking at the USDA zone info.

Planting Calendar for Mimulus

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

Since mimulus do not do well in cold weather you have to wait until after the last frost before you can plant them.

The earliest that you can plant mimulus in Zone 4a is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant mimulus and expect a good harvest is probably August. Any later than that and your mimulus may not have a chance to fully mature. Starting your mimulus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Zone 4a the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -30°F.

Since the USDA zone info for Zone 4a may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Zone 4a you get surprised by a frost after May 15 so just be sure to be ready to cover your mimulus if you have a surprise late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.