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.

In Washington you can estimate when it's the best time to plant rhubarb by looking at the USDA zone info.

Planting Calendar for Rhubarb

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

Rhubarb do well in some cold which tells us that you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant rhubarb in Washington 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 really do well. Starting your rhubarb indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Washington is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in Washington last frost occurs after April 15 so make sure that you are prepared to protect your rhubarb in the event of a late frost.

USDA Zone Info for Washington

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 Washington

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