Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. 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 Zone 4b should be reviewed to figure out when to plant kohlrabi.

Planting Calendar for Kohlrabi

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

Kohlrabi do well in moderate cold which tells us that you can plant them a little bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant kohlrabi in Zone 4b 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 kohlrabi and expect a good harvest is probably August. If you wait any later than that and your kohlrabi may not have a chance to fully mature. If you are starting your kohlrabi indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Zone 4b. In the coldest months of winter you should expect an average low temperature of -25°F.

Since the USDA zone info for Zone 4b may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Zone 4b last frost occurs after May 15 so always be ready to protect your kohlrabi in the event of a late frost.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

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