Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's a good idea to estimate when it's possible to plant sweet potatos by reviewing the USDA zone info for Helena.

Planting Calendar for Sweet Potatos

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

Since sweet potatos do not do well in cold weather it is necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant sweet potatos in Helena 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. You probably don't want to wait any later than that or else your sweet potatos may not have a chance to fully mature. You can get started a few weeks earlier by starting your sweet potatos indoors.

Last Frost Date

On average all chance of frost has passed is on March 15 in Helena. You can expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Helena may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Helena it frosts late in the year after March 15 be ready to cover your sweet potatos in the event of one of those late frosts.

USDA Zone Info for Helena

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 Helena

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