The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant purple bell vines in Caribou should be estimated by using the USDA zone info.

Planting Calendar for Purple Bell Vines

Frost tolerance for purple bell vines:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant purple bell vines slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant purple bell vines in Caribou 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 purple bell vines and expect a good harvest is probably August. Any later than that and your purple bell vines may not have a chance to really do well. You can get started a few weeks earlier by starting your purple bell vines indoors.

Last Frost Date

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

Since the USDA zone info for Caribou is an average the actual date of last frost will vary from year to year. Since half of the time in Caribou last frost occurs after May 15 be ready to cover your purple bell vines if you have a late frost.

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.