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.

You can determine when it's the best time to plant asters in Missoula by referring to the USDA zone info.

Planting Calendar for Asters

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

Asters can survive in mild cold which tells us that you can plant them just a bit earlier in the year than more sensitive plants.

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

The last month that you can plant asters and expect a good harvest is probably September. If you wait any later than that and your asters may not have a chance to fully mature. You can get started a few weeks earlier by starting your asters indoors.

Last Frost Date

The average date of last frost is April 15 in Missoula. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Missoula may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Missoula you get a frost after April 15 so just be sure to be ready to cover your asters in the event of one of those late frosts.

USDA Zone Info for Missoula

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Missoula

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