Spring 2026 in Ontario has been unusually cool, even cold, challenging gardeners who are eager to plant. However, with a few simple strategies, you and your plants can weather the late frosts.
Understanding the Risks of Early Planting
Many gardeners in southern Ontario adhere to the rule of not planting before Victoria Day. However, experienced gardeners often start earlier, planting begonias, impatiens, and pansies as early as late April. Early planting gives young plants a head start, allowing them to establish strong root systems and bloom earlier. Yet, the risk of a late May frost remains a concern.
How to Protect Your Plants from Frost
If temperatures are predicted to drop below 3 or 4 degrees Celsius, take action. First, water the plants thoroughly with lukewarm water. Then, apply a generous layer of mulch around the base, leaving a gap of 1-2 inches from the stems to prevent rot. Cover the bed with old bedsheets or pillowcases, securing the edges with stones or bricks to prevent cold air from seeping in. Avoid using plastic or garbage bags, as they can overheat and smother plants, and are environmentally unfriendly.
For planters or window boxes, bring them indoors overnight if possible. If not, wrap them in bedsheets. A clever technique for small plants is to cut a 1.5-liter pop bottle in half and place it over the plant. The bottom half acts as a mini-cloche, and the top half can have the cap removed for ventilation.
After the Frost
Once the sun rises and the air warms, gently remove the covers to let the plants bask in the sun. Unless there was a severe frost (several degrees below zero), your plants should recover. Remember, a little preparation goes a long way in ensuring your garden thrives despite unpredictable spring weather.
