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.

By using the USDA zone info for Ontario you should be able to determine when it's a good idea to plant rhubarb.

Planting Calendar for Rhubarb

Frost tolerance for rhubarb:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since rhubarb are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than more sensitive plants.

The earliest that you can plant rhubarb 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 rhubarb and expect a good harvest is probably September. You probably don't want to wait any later than that or else your rhubarb may not have a chance to really do well. Starting your rhubarb indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ontario. You should expect an average low temperature of -5°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Ontario and it will vary from year to year. Half of the time in Ontario it frosts late in the year after April 15 so always be ready to protect your rhubarb if you have one of those late frosts.

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.