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

The earliest that you can plant bishop's weed in Ontario should be figured out by referring to the USDA zone info.

Planting Calendar for Bishop's Weed

Frost tolerance for bishop's weed:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since bishop's weed are very cold tolerant you can plant them earlier in the year than other plants that might not handle the cold.

The earliest that you can plant bishop's weed in Ontario is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant bishop's weed and expect a good harvest is probably September. You probably don't want to wait any later than that or else your bishop's weed may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your bishop's weed indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Ontario. In the coldest months of winter you should expect an average low temperature of -5°F.

Remember that USDA zone info for Ontario is an average and the actual date of last frost is different every year. Half of the time in Ontario last frost occurs after April 15 so be sure to be ready to cover your bishop's weed if you have a 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.