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

It's a good idea to estimate when it's a good idea to plant celeriac by using the USDA zone info for Zone 4a.

Planting Calendar for Celeriac

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

You can plant celeriac just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant celeriac in Zone 4a 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 fully mature. If you are starting your celeriac indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Zone 4a. In the coldest months of winter you can expect an average low temperature of -30°F.

Keep in mind that USDA zone info for Zone 4a 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 Zone 4a it frosts late in the year after May 15 so be sure to be ready to cover your celeriac 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.