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

By using the USDA zone info for Iron Mountain it's possible to determine when to plant alternaria.

Planting Calendar for Alternaria

Frost tolerance for alternaria:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Alternaria are not cold tolerant which tells us that you really should wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant alternaria in Iron Mountain 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 alternaria and expect a good harvest is probably August. Any later than that and your alternaria may not have a chance to really do well. You can get started a little bit earlier by starting your alternaria indoors.

Last Frost Date

In Iron Mountain 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.

Since the USDA zone info for Iron Mountain is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Iron Mountain last frost occurs after May 15 so make sure that you are prepared to cover your alternaria if you have 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.