When to Plant Corn in Washington, IA

One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant corn in Washington should be estimated by using the USDA zone info.

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Planting Calendar for Corn

Frost tolerance for corn: Not tolerant of frost.
When to plant: After the last frost when the weather gets warmer.

Corn require warm weather which means that it is important to wait until it warms up after the last frost has passed before you can plant them.

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

The earliest that you can plant corn in Washington is April. However, you really should wait until May if you don't want to take any chances.

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

Last Frost Date

On average the last frost has passed is on April 15 in Washington. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Washington and it will vary from year to year. Since half of the time in Washington you get a frost after April 15 be ready to protect your corn 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.