The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant calla lily in Havre should be estimated by referring to the USDA zone info.

Planting Calendar for Calla Lily

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

Calla Lily require warm weather which tells us that you must wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant calla lily 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 calla lily and expect a good harvest is probably August. If you wait any later than that and your calla lily may not have a chance to fully mature. If you are starting your calla lily indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Always 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 will vary from year to year. Since half of the time in Havre last frost occurs after May 15 be ready to protect your calla lily in the event of a surprise 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.