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

You should be able to figure out when it's possible to plant spearmint by reviewing the USDA zone info for Green River.

Planting Calendar for Spearmint

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

Spearmint do well in cold which tells us that you can plant them much earlier than other plants that might not handle the cold.

The earliest that you can plant spearmint in Green River 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 spearmint and expect a good harvest is probably August. Any later than that and your spearmint may not have a chance to really do well. You can get started a couple of weeks earlier by starting your spearmint indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Green River. You can expect an average low temperature of -25°F in the coldest months of winter.

Keep in mind that USDA zone info for Green River is an average and the actual date of last frost changes from year to year. Since half of the time in Green River you get a frost after May 15 be ready to cover your spearmint in the event of a late frost.

USDA Zone Info for Green River

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 Green River

You may be interested in your other planting guides for Green River.