Before planting it is a good idea to find your USDA Zone info to determine your garden 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 Portland can be reviewed to figure out when it's possible 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 are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant celeriac in Portland 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 grow to maturity. Starting your celeriac indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Portland the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Portland and it will vary from year to year. Half of the time in Portland it frosts late in the year after April 15 so be sure to be ready to cover your celeriac in the event of one of those late frosts.

USDA Zone Info for Portland

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 Portland

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