When to Plant Rhubarb in Washington, IA

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.

One way of getting a good idea when it's the best time to plant rhubarb is to examine the USDA zone info for Washington.

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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 moderate cold which means that you can plant them a little bit earlier than other frost tender plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant rhubarb
Possibly ok, but a risky time to plant rhubarb
Probably not a good time to plant rhubarb

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. If you wait any later than that and your rhubarb may not have a chance to fully mature. You can get started a little bit earlier by starting your rhubarb indoors.

Last Frost Date

In Washington the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Remember that USDA zone info for Washington is just an average and the actual date of last frost is different every year. Half of the time in Washington last frost occurs after April 15 so make sure that you are ready to cover your rhubarb if you have a surprise 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.