One of the best tools that you have as gardeners to help us estimate 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.

The USDA zone info for Billings can be read to determine when you can plant asters.

Planting Calendar for Asters

Frost tolerance for asters:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant asters a little bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

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

The last month that you can plant asters and expect a good harvest is probably August. Any later than that and your asters may not have a chance to fully mature. Starting your asters indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on May 15 in Billings. In the coldest months of winter you can expect an average low temperature of -25°F.

It's important to remember that USDA zone info for Billings is not always accurate and the actual date of last frost is different every year. Half of the time in Billings it frosts late in the year after May 15 so make sure that you are ready to protect your asters in the event of a surprise late frost.

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.