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

You will be able to estimate when it's the best time to plant foxglove by checking out the USDA zone info for Zone 4b.

Planting Calendar for Foxglove

Frost tolerance for foxglove:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Foxglove do well in moderate cold which tells us that you can start planting them earlier than more sensitive plants.

The earliest that you can plant foxglove in Zone 4b is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant foxglove and expect a good harvest is probably August. You probably don't want to wait any later than that or else your foxglove may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your foxglove indoors.

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 is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 4b it frosts late in the year after May 15 be ready to protect your foxglove in the event of 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.