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.

A way of determining when to plant twinspur is to examine the USDA zone info for Caribou.

Planting Calendar for Twinspur

Frost tolerance for twinspur:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Twinspur do well in moderate cold which means that you can start planting them earlier than more sensitive plants.

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

The last month that you can plant twinspur and expect a good harvest is probably August. If you wait any later than that and your twinspur may not have a chance to fully mature. If you are starting your twinspur indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last 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.

Since the USDA zone info for Caribou may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Caribou you get a frost after May 15 be ready to protect your twinspur if you have a surprise 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.