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 first chance to plant sweet potato vine in Portland should be figured out by referring to the USDA zone info.

Planting Calendar for Sweet Potato Vine

Frost tolerance for sweet potato vine:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since sweet potato vine require warm weather you really should wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant sweet potato vine in Portland 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 potato vine and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sweet potato vine may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your sweet potato vine indoors.

Last Frost Date

In Portland 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 Portland is not always accurate the actual date of last frost is different every year. Half of the time in Portland there is a last frost after April 15 so just be sure to be ready to protect your sweet potato vine if you have a late frost.

USDA Zone Info for Portland

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 Portland

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