The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By checking out the USDA zone info for Ottawa you will be able to determine when you can plant skullcap.

Planting Calendar for Skullcap

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

Skullcap require warm weather which tells us that it is important to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant skullcap in Ottawa 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. You can get started a couple of weeks earlier by starting your skullcap indoors.

Last Frost Date

The average date of last frost is April 15 in Ottawa. In the coldest months of winter you should expect an average low temperature of -10°F.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Ottawa and it is different every year. Since half of the time in Ottawa you get surprised by a frost after April 15 be ready to protect your skullcap if you have a surprise late frost.

USDA Zone Info for Ottawa

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 Ottawa

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