The USDA Zone info is a great tool for gardeners to help us determine 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.

The best time to plant blue throatwort in Merrill can be estimated by referring to the USDA zone info.

Planting Calendar for Blue Throatwort

Frost tolerance for blue throatwort:	Not tolerant of frost.
When to plant:	After the last frost.

It's probably not a good idea to plant blue throatwort until after the last frost because they require warm weather.

The earliest that you can plant blue throatwort in Merrill is May. However, you really should wait until June if you don't want to take any chances.

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

Last Frost Date

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

Since the USDA zone info for Merrill is just an average the actual date of last frost is different every year. Since half of the time in Merrill there is a last frost after May 15 be ready to protect your blue throatwort in the event of a surprise late frost.

USDA Zone Info for Merrill

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 Merrill

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