Before planting it is a good idea to find your USDA Zone info to estimate your garden 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 primula in Iron Mountain should be estimated by looking at the USDA zone info.

Planting Calendar for Primula

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

Primula do ok in cold weather which tells us that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant primula in Iron Mountain 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. If you wait any later than that and your primula may not have a chance to grow to maturity. You can get started a little bit earlier by starting your primula indoors.

Last Frost Date

On average the last frost is on May 15 in Iron Mountain. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Iron Mountain may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Iron Mountain you get a frost after May 15 so make sure that you are ready to cover your primula in the event of a surprise late frost.

USDA Zone Info for Iron Mountain

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 Iron Mountain

You may be interested in your other planting guides for Iron Mountain.