One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of determining when it's the best time to plant celeriac is to consult the USDA zone info for Roma.

Planting Calendar for Celeriac

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

Celeriac tend to make it in mild cold which tells us that you can plant them a little earlier in the year than other plants that might not handle the cold.

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

The last month that you can plant celeriac and expect a good harvest is probably October. You probably don't want to wait any later than that or else your celeriac may not have a chance to grow to maturity. 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 February 15 in Roma. In the coldest months of winter you should expect an average low temperature of 25°F.

Since the USDA zone info for Roma is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Roma you get a frost after February 15 be ready to cover your celeriac if you have one of those late frosts.

USDA Zone Info for Roma

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Roma

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