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.

By checking out the USDA zone info for Portland you will be able to determine when it's possible to plant rhubarb.

Planting Calendar for Rhubarb

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

Rhubarb tend to make it in some cold which tells us that you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant rhubarb 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 rhubarb and expect a good harvest is probably September. You probably don't want to wait any later than that or else your rhubarb may not have a chance to grow to maturity. If you are starting your rhubarb indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Portland is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Portland you get a frost after April 15 be ready to cover your rhubarb if you have a late frost.

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.