When to Plant Skullcap in Sullivan, IL

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

You can estimate when it's possible to plant skullcap in Sullivan by checking out the USDA zone info.


Planting Calendar for Skullcap

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

It's a bad idea to plant skullcap until after the last frost because they are not cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant skullcap
Possibly ok, but a risky time to plant skullcap
Probably not a good time to plant skullcap

The earliest that you can plant skullcap in Sullivan 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 grow to maturity. If you are starting your skullcap indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Sullivan. In the coldest months of winter you should expect an average low temperature of -10°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 Sullivan and it changes from year to year. Since half of the time in Sullivan last frost occurs after April 15 be ready to cover your skullcap if you have a late frost.

USDA Zone Info for Sullivan

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 Sullivan

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