Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of making a decision about when it's a good idea to plant twinspur is to use the USDA zone info for Iron Mountain.

Planting Calendar for Twinspur

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

Twinspur do well in moderate cold which tells us that you can start planting them earlier than more sensitive plants.

The earliest that you can plant twinspur 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 twinspur and expect a good harvest is probably August. Any later than that and your twinspur may not have a chance to grow to maturity. If you are starting your twinspur indoors then you might be able to get away with starting them a few weeks earlier.

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.

It's important to remember that USDA zone info for Iron Mountain is an average and the actual date of last frost is different every year. Since half of the time in Iron Mountain last frost occurs after May 15 be ready to cover your twinspur 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.