One of the best tools that you have as gardeners to help us estimate 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.

The first chance to plant skullcap in Naperville can be figured out by reviewing the USDA zone info.

Planting Calendar for Skullcap

Frost tolerance for skullcap:	Not tolerant of frost.
When to plant:	After the last frost.

Since skullcap do not do well in cold weather it is important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant skullcap in Naperville 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 skullcap and expect a good harvest is probably August. If you wait any later than that and your skullcap may not have a chance to really do well. Starting your skullcap indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Naperville. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Naperville is not always accurate the actual date of last frost is different every year. Half of the time in Naperville last frost occurs after April 15 so always be ready to cover your skullcap if you have one of those late frosts.

USDA Zone Info for Naperville

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 Naperville

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