Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The earliest that you can plant blue throatwort in Princeton can be figured out by reviewing the USDA zone info.

Planting Calendar for Blue Throatwort

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

You can not plant blue throatwort until after the last frost because they are not cold tolerant.

The earliest that you can plant blue throatwort in Princeton 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 fully mature. If you are starting your blue throatwort indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Princeton. In the coldest months of winter you can expect an average low temperature of -30°F.

Always keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Princeton and it will vary from year to year. Half of the time in Princeton it frosts late in the year after May 15 so always be ready to protect your blue throatwort in the event of a late frost.

USDA Zone Info for Princeton

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 Princeton

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