When to Plant Sweet Potatos in Mount Vernon, WA

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of figuring out when it's possible to plant sweet potatos is to look at the USDA zone info for Mount Vernon.


Planting Calendar for Sweet Potatos

Frost tolerance for sweet potatos: Not tolerant of frost.
When to plant: After all chance of frost has passed.

It's not a good idea to plant sweet potatos until after the last frost has passed because they do not do well in cold weather.

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

The earliest that you can plant sweet potatos in Mount Vernon 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 little bit earlier by starting your sweet potatos indoors.

Last Frost Date

The average date of last frost is March 15 in Mount Vernon. In the coldest months of winter you can expect an average low temperature of 10°F.

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 Mount Vernon and it changes from year to year. Since half of the time in Mount Vernon it frosts late in the year after March 15 be ready to protect your sweet potatos if you have one of those late frosts.

USDA Zone Info for Mount Vernon

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 Low10°F
Highest Expected Low15°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 Mount Vernon

You may be interested in your other planting guides for Mount Vernon.