One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Rock Springs you can figure out when it's a good idea to plant four o' clock by reviewing the USDA zone info.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since four o' clock require warm weather you need 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 in Rock Springs 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. You probably don't want to wait any later than that or else your four o' clock may not have a chance to really do well. 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 Rock Springs. In the coldest months of winter you can expect an average low temperature of -20°F.

Just be sure to remember that USDA zone info for Rock Springs is not always accurate and the actual date of last frost is different every year. Since half of the time in Rock Springs last frost occurs after April 15 be ready to cover your four o' clock if you have a surprise late frost.

USDA Zone Info for Rock Springs

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 Rock Springs

You may be interested in your other planting guides for Rock Springs.