One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of estimating when you can plant foxglove is to consult the USDA zone info for Johnston.

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 a little bit of cold which tells us that you can plant them a little earlier in the year than plants that are more sensitive to the cold.

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

The last month that you can plant foxglove and expect a good harvest is probably September. Any later than that and your foxglove may not have a chance to fully mature. If you are starting your foxglove indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Johnston the average date of last frost happens on April 15. You should expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Johnston is just an average the actual date of last frost will vary from year to year. Half of the time in Johnston you get a frost after April 15 so always be ready to cover your foxglove in the event of a surprise late frost.

USDA Zone Info for Johnston

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Johnston

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