One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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 Billings you can figure out when to plant pentas by checking out the USDA zone info.

Planting Calendar for Pentas

Frost tolerance for pentas:	Not tolerant of frost.
When to plant:	After the last frost.

Since pentas are not cold tolerant it's necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant pentas in Billings is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant pentas and expect a good harvest is probably August. If you wait any later than that and your pentas may not have a chance to fully mature. Starting your pentas indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Billings. It might get as low as -25°F during the coldest months of winter.

Keep in mind that USDA zone info for Billings is just an average and the actual date of last frost will vary from year to year. Since half of the time in Billings you get surprised by a frost after May 15 be ready to cover your pentas in the event of one of those late frosts.

USDA Zone Info for Billings

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Billings

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