The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of estimating when it's the best time to plant portulaca is to refer to the USDA zone info for Casper.

Planting Calendar for Portulaca

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

Since portulaca do not do well in cold weather you really should wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant portulaca in Casper 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 portulaca and expect a good harvest is probably August. Any later than that and your portulaca may not have a chance to grow to maturity. If you are starting your portulaca indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Casper. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind 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 Casper and it is different every year. Since half of the time in Casper it frosts late in the year after April 15 be ready to cover your portulaca in the event of a late frost.

USDA Zone Info for Casper

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Casper

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