One of the best tools that you have as gardeners to help us estimate 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 USDA zone info for Wyoming can be used to figure out when it's the best time to plant four o' clock.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since four o' clock do not do well in cold weather you have to wait until after the last frost has passed before you can plant them.

The earliest that you can plant four o' clock in Wyoming 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 and expect a good harvest is probably August. Any later than that and your four o' clock may not have a chance to fully mature. You can get started a little bit earlier by starting your four o' clock indoors.

Last Frost Date

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

Keep in mind that USDA zone info for Wyoming is just an average and the actual date of last frost is different every year. Since half of the time in Wyoming there is a last frost after April 15 be ready to protect your four o' clock if you have a surprise late frost.

USDA Zone Info for Wyoming

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 Wyoming

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