One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when it's a good idea to plant browallia by reviewing the USDA zone info for Superior.

Planting Calendar for Browallia

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

It's a bad idea to plant browallia until after the last frost has passed because they are not cold tolerant.

The earliest that you can plant browallia in Superior 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 browallia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your browallia may not have a chance to grow to maturity. If you are starting your browallia indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Superior. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Superior is not always accurate the actual date of last frost will vary from year to year. Half of the time in Superior you get a frost after May 15 so be sure to be ready to protect your browallia if you have a late frost.

USDA Zone Info for Superior

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Superior

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