One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Caribou can be reffered to in order to figure out when it's possible to plant browallia.

Planting Calendar for Browallia

Frost tolerance for browallia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably a bad idea to plant browallia until after the last frost has passed because they require warm weather.

The earliest that you can plant browallia in Caribou 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 fully mature. You can get started a couple of weeks earlier by starting your browallia indoors.

Last Frost Date

On average all chance of frost has passed is on May 15 in Caribou. In the coldest months of winter you can expect an average low temperature of -30°F.

It's important to remember that USDA zone info for Caribou is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Caribou last frost occurs after May 15 be ready to protect your browallia in the event of one of those late frosts.

USDA Zone Info for Caribou

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 Caribou

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