One of the best tools that you have as gardeners to help us determine 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.

One way of estimating when to plant mustard greens is to use the USDA zone info for Caribou.

Planting Calendar for Mustard greens

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

Since mustard greens are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant mustard greens 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 mustard greens and expect a good harvest is probably August. If you wait any later than that and your mustard greens may not have a chance to really do well. You can get started a little bit earlier by starting your mustard greens indoors.

Last Frost Date

In Caribou the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Caribou may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Caribou you get surprised by a frost after May 15 be ready to protect your mustard greens 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.