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.

The earliest that you can plant sweet potatos in Washington should be figured out by checking out the USDA zone info.

Planting Calendar for Sweet Potatos

Frost tolerance for sweet potatos:	Not tolerant of frost.
When to plant:	After the last frost.

Sweet Potatos require warm weather which tells us that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant sweet potatos 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 sweet potatos and expect a good harvest is probably August. If you wait any later than that and your sweet potatos may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your sweet potatos indoors.

Last Frost Date

The average date of last frost is March 15 in Washington. It might get as low as 10°F during the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Washington and it changes from year to year. Since half of the time in Washington you get surprised by a frost after March 15 be ready to protect your sweet potatos in the event of a late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Washington

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