Given the late spring here in southern Ontario (GTA area) this year and still cool temperatures at night especially, what advice do you have about when it is best to put into the garden the warm-weather loving plants such as tomatoes, cucumbers etc.? I’ve heard the usual rule of thumb of “after the May long weekend”, but it seems like it still won’t be warm enough. Should I wait until beginning of June to put into the garden the tomatoes I started from seed?
As noted in a response already posted to our website (When to plant my tomato plants”, at https://www.torontomastergardeners.ca/index.php/askagardener/when-to-plant-my-tomato-plants/ ), on or after the Victoria Day weekend is generally a good time to start planting tomato plants. The key issue is when all risk of frost has passed in your area. Another Q&A “Tomatoes growing season” (at https://www.torontomastergardeners.ca/index.php/askagardener/tomatoes-growing-season/ ) provides a bit more detail.
The Ontario government, in its “Climate Zones and Planting Dates for Vegetables in Ontario” at https://www.omafra.gov.on.ca/english/crops/facts/climzoneveg.htm provides climate zone maps that will give you some level of comfort. For example, in the Toronto area, there will be no frost after April 30 fifty percent of the time (i.e., one year of every two years) and there is only a 25% risk of frost occurring 7 days following this date.
A recent Global News article posted May 12 2014 “Gardeners, rejoice: Toronto has (probably) seen the spring’s last frost” (at https://globalnews.ca/news/1321704/gardeners-rejoice-toronto-has-probably-seen-the-springs-last-frost/ ) highlights that after May 10, a spring frost is highly unlikely. They point out that the latest spring frost from 75 years of data was May 29. As well, 95% of last frosts in Toronto have occurred before May 24.
So while it’s wise to keep an eye on the weather, especially this year, a good target date for you to plant those dear tomatoes would be around May 24.