The USDA Zone info is a great tool for gardeners to help us figure out 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.

You will be able to estimate when it's the best time to plant celeriac by looking at the USDA zone info for Zone 4b.

Planting Calendar for Celeriac

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

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

The earliest that you can plant celeriac 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 celeriac and expect a good harvest is probably August. Any later than that and your celeriac may not have a chance to really do well. If you are starting your celeriac indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Zone 4b. You should expect an average low temperature of -25°F in the coldest months of winter.

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. Since half of the time in Zone 4b it frosts late in the year after May 15 be ready to cover your celeriac 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.