The USDA Zone info is a great tool for gardeners to help us estimate 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.

The best time to plant four-o-clock flower in Casper can be determined by looking at the USDA zone info.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since four-o-clock flower do not do well in cold weather you have to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant four-o-clock flower 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 four-o-clock flower and expect a good harvest is probably August. Any later than that and your four-o-clock flower may not have a chance to really do well. Starting your four-o-clock flower indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Casper. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Casper may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Casper you get surprised by a frost after April 15 be ready to cover your four-o-clock flower if you have a surprise 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.