When to Plant Potatos in Washington, IL

Before planting it is a good idea to find your USDA Zone info to estimate 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 Washington should be reffered to in order to determine when it's a good idea to plant potatos.


Planting Calendar for Potatos

Frost tolerance for potatos: Very tolerant of frost.
When to plant: Up to 7 weeks before last frost.

Since potatos do well in cold you can plant them quite a bit earlier in the year than other frost tender plants.

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

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

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.

Since the USDA zone info for Washington is an average the actual date of last frost changes from year to year. Since half of the time in Washington you get surprised by a frost after April 15 be ready to protect your potatos 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.