Common Calendar Dates for Planting in Ontario

Often we teach or are taught the date, but not the why behind it. This oversimplifies gardening and leaves out key information that has the potential of leading to great gardening successes. So why do we plant on the May 24 weekend in Southern Ontario?

Why do we plant on May 24?

Frost Dates. Except that frost dates have changed over the years, but because many gardeners do not know the “why” behind May 24, they continue to hold this weekend as official planting time.

We dive into frost dates more in depth here.

Why are seeds started on St. Patrick’s Day?

Our first and last frost dates dictate the length of our growing season. Plants that require more days then our growing season, require starting indoors. Many seeds require an additional 6-8 weeks. Counting back from Mid-May (previous last frost), 8 weeks lands us on St. Patrick’s day.

As a general rule of thumb, this date works but applying a blanket rule to all seeds might leave a gardener struggling with leggy plants started too soon, and others that didn’t get germinated early enough. You may miss out on prime growing season for cold hardy crops, since our ‘spring’ is a very short window.

Putting the spice in Valentines Day.

A lesser known date, but another common association is Valentine’s Day and starting peppers. These usually require an additional 10-12 weeks of growing time which lands right around, Valentine’s Day! There are other crops that can use starting at this point as well:

So when should you plant your vegetable garden? We cover that here.