One of the first steps you take when you are figuring out 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 blue throatwort in Smithfield can be estimated by reviewing 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.

Blue Throatwort are not cold tolerant which tells us that you really should wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant blue throatwort in Smithfield 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 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. You can get started a few weeks earlier by starting your blue throatwort indoors.

Last Frost Date

In Smithfield the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Smithfield is not always accurate and the actual date of last frost is different every year. Half of the time in Smithfield it frosts late in the year after April 15 so be sure to be ready to protect your blue throatwort in the event of a surprise late frost.

USDA Zone Info for Smithfield

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Smithfield

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