Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Alton it's a good idea to figure out when it's possible to plant skullcap.

Planting Calendar for Skullcap

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

It's not a good idea to plant skullcap until after the last frost because they require warm weather.

The earliest that you can plant skullcap in Alton 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. You probably don't want to wait any later than that or else your skullcap may not have a chance to really do well. If you are starting your skullcap indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Alton the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

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 Alton and it changes from year to year. Since half of the time in Alton last frost occurs after April 15 be ready to cover your skullcap in the event of a late frost.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Alton

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