One of the first steps you take when you are figuring out your gardening schedule is find your 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 should be used to determine when it's a good idea to plant erysimum.

Planting Calendar for Erysimum

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

Erysimum tend to make it in moderate cold which means that you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant erysimum 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 erysimum and expect a good harvest is probably August. Any later than that and your erysimum may not have a chance to really do well. Starting your erysimum indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Caribou. In the coldest months of winter you can expect an average low temperature of -30°F.

Always keep in mind that USDA zone info for Caribou is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Caribou last frost occurs after May 15 so always be ready to protect your erysimum in the event of 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.