One of the best tools that you have as gardeners to help us determine 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 to plant calendula in Havre by looking at the USDA zone info.

Planting Calendar for Calendula

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

Since calendula do well in moderate cold you can plant them a bit earlier in the year than other frost tender plants.

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

The last month that you can plant calendula and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calendula may not have a chance to grow to maturity. Starting your calendula indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

It's important to remember that USDA zone info for Havre is not always accurate and the actual date of last frost is different every year. Half of the time in Havre you get a frost after May 15 so just be sure to be ready to cover your calendula if you have 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.