I bought Marha Washington Geraniums at the Nursery in early May.
Do I have to wait until late May to put these plants outside.
Thank you for asking this question from the Toronto Master Gardeners. Plants like your very pretty Martha Washington geraniums that you bought from the nursery should already be hardened for the outdoors.
However, there are two things you should consider before setting your plants outside permanently: the last-frost date for Toronto is May 11-20; and the Martha Washington geranium only flowers when the temperature is at least between 10-16 C degrees.
Toronto’s night-time temperatures are still dropping below 10 degrees, and the long-term forecast for the next 7 days predicts very cold nights. You might consider setting the plants out during the day for the next week or so, and bringing them in at the end of the day. Set the plants outside permanently when the weather is forecast for warmer nights.
May 7, 2021