One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Johnston it's possible to figure out when you can plant celeriac.

Planting Calendar for Celeriac

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

Celeriac do well in moderate cold which tells us that you can start planting them earlier than more sensitive plants.

The earliest that you can plant celeriac in Johnston is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant celeriac and expect a good harvest is probably September. If you wait any later than that and your celeriac may not have a chance to really do well. Starting your celeriac indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Johnston. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Johnston is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Johnston there is a last frost after April 15 so be sure to be ready to protect your celeriac in the event of a late frost.

USDA Zone Info for Johnston

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Johnston

You may be interested in your other planting guides for Johnston.