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.

A common way of estimating when it's possible to plant alternaria is to examine the USDA zone info for Rock Springs.

Planting Calendar for Alternaria

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

Since alternaria require warm 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 alternaria 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 alternaria and expect a good harvest is probably August. You probably don't want to wait any later than that or else your alternaria may not have a chance to really do well. You can get started a few weeks earlier by starting your alternaria indoors.

Last Frost Date

The average date of last frost is April 15 in Rock Springs. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Rock Springs is just an average the actual date of last frost will vary from year to year. Since half of the time in Rock Springs you get a frost after April 15 be ready to cover your alternaria 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.