One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when it's the best time to plant achimenes is to check out the USDA zone info for Billings.

Planting Calendar for Achimenes

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

Since achimenes are not cold tolerant it's important to wait until after the last frost before you can plant them.

The earliest that you can plant achimenes 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 achimenes and expect a good harvest is probably August. You probably don't want to wait any later than that or else your achimenes may not have a chance to fully mature. You can get started a few weeks earlier by starting your achimenes indoors.

Last Frost Date

In Billings the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Billings is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Billings you get a frost after May 15 be ready to protect your achimenes if you have 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.