Mastering Cold Crop Veggie Planting in Southern Ontario with Tanya Olsen

As mid-April ushers in unpredictable temperature dips in Southern Ontario, gardeners must remain vigilant in protecting their tender crops outdoors. Tanya Olsen, third-generation owner of Royal City Nursery and a Professor in the Horticulture Program at Humber College shares her top tips for planting your cold crops outside this time of year and how to protect them during spells of overnight frost. 

Watch our latest video on YouTube to learn more or scroll to continue reading. 

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One effective method of protecting your crops is utilizing the hoop and frost cloth technique. Hoops create structure to support the frost cloth (ensure its thickness is around 1.5 ounces) forming a protective heat pocket that shields from frost damage. This method is particularly beneficial for maintaining warmth overnight or during exceptionally cold days. 

When the danger of frost has gone, switch out your frost cloth to a lightweight option, around 0.6 ounces thick. This type of cloth provides adequate protection against the elements while allowing the sunlight to filter through. It serves as a shield against sun-scald on squash and melons, and can also be used to protect cabbage and potatoes from damage caused by potato beetles and cabbage loopers. 

Planting Cold Crops

Cold crop vegetables are ideal for planting in mid-April, provided they are protected by a frost cloth. These crops include: beets, broccoli, broccolini, brussel sprouts, and cauliflower. Swiss chard is another excellent cold crop choice, especially suitable for container planting due to its vibrant colours. Additionally, kale, leeks, and vegetables from the onion family thrive in cooler temperatures. 

However, tomatoes and peppers should remain indoors in a sunny spot until the risk of frost has passed. 

Planting Tips

• Plant cold crops in the ground from mid April to May, but make sure they are adequately protected by a frost cloth (sometimes called a frost blanket). 
• To protect clusters of crops, use rocks or slightly bury the sides of the cloth into the ground around the crops to prevent it from being blown away. 
• Replace the frost cloth with a thinner one once the danger of frost has subsided to protect your potatoes, squash, and melons from sun-scald and insects. 

With these tips, you can successfully plant and protect your cold crop vegetables during the unpredictable weather of mid-April & early May. Explore our wide range of cold crop veggies in-store at Royal City Nursery and be sure to pick up frost cloth too! Our experts are always happy to help and advise you on what’s best for your garden or container planting dreams. Happy planting!