The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Ontario you can estimate when it's possible to plant skullcap by referring to the USDA zone info.

Planting Calendar for Skullcap

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

Since skullcap require warm weather you really should wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant skullcap in Ontario 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. Any later than that and your skullcap may not have a chance to grow to maturity. You can get started a little bit earlier by starting your skullcap indoors.

Last Frost Date

The average date of last frost is April 15 in Ontario. It might get as low as -5°F during the coldest months of winter.

Remember that USDA zone info for Ontario is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Ontario there is a last frost after April 15 so always be ready to protect your skullcap in the event of a surprise late frost.

USDA Zone Info for Ontario

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Ontario

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