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

A common way of getting a good idea when it's a good idea to plant lemon balm is to use the USDA zone info for Duluth.

Planting Calendar for Lemon balm

Frost tolerance for lemon balm:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since lemon balm do ok in moderate cold you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant lemon balm in Duluth is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant lemon balm and expect a good harvest is probably August. If you wait any later than that and your lemon balm may not have a chance to grow to maturity. If you are starting your lemon balm indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Duluth and it changes from year to year. Since half of the time in Duluth you get a frost after May 15 be ready to cover your lemon balm if you have a surprise late frost.

USDA Zone Info for Duluth

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 Duluth

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