One of the first steps you take when you are determining 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.

It's possible to estimate when it's possible to plant borage by checking out the USDA zone info for Missoula.

Planting Calendar for Borage

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

Since borage are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant borage 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 borage and expect a good harvest is probably September. If you wait any later than that and your borage may not have a chance to really do well. If you are starting your borage indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Missoula. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Missoula is an average the actual date of last frost is different every year. Since half of the time in Missoula you get a frost after April 15 be ready to protect your borage 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.