One of the first steps you take when you are getting a good idea 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.

The USDA zone info for Marshall can be looked at to figure out when it's the best time to plant blue throatwort.

Planting Calendar for Blue Throatwort

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

Blue Throatwort are not cold tolerant which means that you must wait until it warms up after the last frost before you can plant them.

The earliest that you can plant blue throatwort in Marshall 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. Any later than that and your blue throatwort may not have a chance to grow to maturity. Starting your blue throatwort indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Marshall. In the coldest months of winter you should expect an average low temperature of -25°F.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Marshall and it can change quite a bit from year to year. Half of the time in Marshall there is a last frost after May 15 so be sure to be ready to protect your blue throatwort in the event of a late frost.

USDA Zone Info for Marshall

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 Marshall

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