One of the best tools that you have as gardeners to help us figure out 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.

One way of getting a good idea when it's possible to plant primula is to use the USDA zone info for Mandan.

Planting Calendar for Primula

Frost tolerance for primula:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Primula tend to make it in quite a bit of cold which tells us that you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant primula in Mandan 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 primula and expect a good harvest is probably August. Any later than that and your primula may not have a chance to grow to maturity. Starting your primula indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Mandan is just an average the actual date of last frost changes from year to year. Since half of the time in Mandan you get surprised by a frost after May 15 be ready to cover your primula if you have a late frost.

USDA Zone Info for Mandan

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 Mandan

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