Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By looking at the USDA zone info for Havre you should be able to figure out when it's possible to plant impatiens.

Planting Calendar for Impatiens

Frost tolerance for impatiens:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Impatiens are not cold tolerant which means that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant impatiens in Havre 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 impatiens and expect a good harvest is probably August. You probably don't want to wait any later than that or else your impatiens may not have a chance to fully mature. Starting your impatiens indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Havre the average date of last frost happens on May 15. You should expect an average low temperature of -30°F in the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Havre and it is different every year. Since half of the time in Havre there is a last frost after May 15 be ready to protect your impatiens if you have a late frost.

USDA Zone Info for Havre

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Havre

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