The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first opportunity to plant salpiglossis in Havre can be figured out by reviewing the USDA zone info.

Planting Calendar for Salpiglossis

Frost tolerance for salpiglossis:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You should not plant salpiglossis until after the last frost because they do not do well in cold weather.

The earliest that you can plant salpiglossis 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 salpiglossis and expect a good harvest is probably August. If you wait any later than that and your salpiglossis may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your salpiglossis indoors.

Last Frost Date

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

Remember that USDA zone info for Havre is not always accurate and the actual date of last frost changes from year to year. Half of the time in Havre last frost occurs after May 15 so make sure that you are ready to cover your salpiglossis if you have one of those late frosts.

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.