One of the first steps you take when you are estimating your gardening schedule is find your 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.

You can figure out when you can plant monarda in Zone 4b by reviewing the USDA zone info.

Planting Calendar for Monarda

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

Monarda do ok in moderate cold which means that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant monarda in Zone 4b 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 monarda and expect a good harvest is probably August. Any later than that and your monarda may not have a chance to really do well. Starting your monarda indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Zone 4b. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Zone 4b may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 4b there is a last frost after May 15 be ready to cover your monarda if you have a late frost.

USDA Zone Info for Zone 4b

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 Zone 4b

You may be interested in your other planting guides for Zone 4b.