The USDA Zone info is a great tool for gardeners to help us figure out your gardening 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 Castle Rock should be used to estimate when to plant celeriac.

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 do well in moderate cold.

The earliest that you can plant celeriac in Castle Rock 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. Any later than that and your celeriac may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your celeriac indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Castle Rock. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Castle Rock is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Castle Rock it frosts late in the year after April 15 be ready to protect your celeriac in the event of a late frost.

USDA Zone Info for Castle Rock

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Castle Rock

You may be interested in your other planting guides for Castle Rock.