One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant lemon balm in Helena should be determined by reviewing the USDA zone info.

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 more sensitive plants.

The earliest that you can plant lemon balm in Helena 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. You probably don't want to wait any later than that or else your lemon balm may not have a chance to really do well. You can get started a couple of weeks earlier by starting your lemon balm indoors.

Last Frost Date

The average date of last frost is May 15 in Helena. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Helena may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Helena last frost occurs after May 15 so make sure that you are ready to protect your lemon balm in the event of a surprise late frost.

USDA Zone Info for Helena

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 Helena

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