The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant crassula in Zone 4a should be estimated by referring to the USDA zone info.

Planting Calendar for Crassula

Frost tolerance for crassula:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant crassula until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant crassula in Zone 4a 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 crassula and expect a good harvest is probably August. Any later than that and your crassula may not have a chance to really do well. You can get started a few weeks earlier by starting your crassula indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4a. You should expect an average low temperature of -30°F in the coldest months of winter.

Since the USDA zone info for Zone 4a is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Zone 4a you get a frost after May 15 so always be ready to protect your crassula if you have one of those late frosts.

USDA Zone Info for Zone 4a

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 Zone 4a

You may be interested in your other planting guides for Zone 4a.