Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of getting a good idea when you can plant portulaca is to examine the USDA zone info for Williston.

Planting Calendar for Portulaca

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

It's probably not a good idea to plant portulaca until after the last frost has passed because they are not cold tolerant.

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

The last month that you can plant portulaca and expect a good harvest is probably August. If you wait any later than that and your portulaca may not have a chance to grow to maturity. Starting your portulaca indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Williston. It might get as low as -30°F during the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Williston and it is different every year. Half of the time in Williston there is a last frost after May 15 so just be sure to be ready to cover your portulaca in the event of a surprise late frost.

USDA Zone Info for Williston

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Williston

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