The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Iron Mountain you will be able to estimate when it's the best time to plant romaine lettuce.

Planting Calendar for Romaine lettuce

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

Romaine lettuce tend to make it in a bit of cold which means that you can plant them a lot earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant romaine lettuce 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 romaine lettuce and expect a good harvest is probably August. If you wait any later than that and your romaine lettuce may not have a chance to fully mature. Starting your romaine lettuce 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 Iron Mountain. You should expect an average low temperature of -30°F in the coldest months of winter.

Keep in mind that USDA zone info for Iron Mountain is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Iron Mountain last frost occurs after May 15 be ready to protect your romaine lettuce if you have a 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.