The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of making a decision about when to plant romaine lettuce is to check out the USDA zone info for Ishpeming.

Planting Calendar for Romaine lettuce

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

Since romaine lettuce are one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant romaine lettuce in Ishpeming 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. You probably don't want to wait any later than that or else 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

In Ishpeming the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Ishpeming may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Ishpeming you get surprised by a frost after May 15 so always be ready to cover your romaine lettuce in the event of a late frost.

USDA Zone Info for Ishpeming

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Ishpeming

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