Many of us in Ottawa are eager to get planting, but the question we are asked most every year is “when can I plant?”
Our answer; it depends on what you are planting! There are two main barriers in the spring that can delay planting; ground thaw and morning frost. The ground thaw is an obvious barrier as if you cannot dig, you cannot plant. Frost damage isn’t as linear as a ground thaw and can occur as late as June. Luckily, you can use products like frost blankets or sprinklers to mitigate frost damage. Frost damage actually occurs early in the morning, typically right before dawn. Gardeners who wake up early should consider leaving frost blankets on their gardens or planters until after sunrise; between 7 and 8am.
Overwintered or dormant trees, evergreens, and shrubs can be planted when the ground has thawed! Since these plants have been acclimated to the cold, you can start planting as soon as you can work the ground. Be sure to water thoroughly but infrequently and use a rooting agent like Root Rescue or Bone Meal to encourage new root growth.
Cold-tolerant annuals like pansies, kale, cabbage or dusty miller can be planted once the ground thaws and the plants have had a chance to “harden off”. If you’re buying from a greenhouse or have raised these plants from seed indoors, you may want to transition these annuals to the outdoors over a couple of days. This helps the plants acclimate to more sun, wind, and cold temperatures better than direct planting.
Any plants with new flowers should only be planted AFTER the risk of frost has passed. Leaves and blossoms that have been forced by greenhouse heat are significantly more tender to the cold and direct sunlight than overwintered outdoor plants. If you’re unsure, just ask one of our garden experts when they would ideally plant!
Annuals, seedlings, and new flowers (from indoors or a greenhouse) should only be planted AFTER the risk of frost has passed. In Ottawa, this is usually between the last week of May and the First week of June.
If you want to add hanging baskets or potted arrangements outdoors, you can always bring them out for the day and shelter them in a garage or under a frost blanket at night. This will help ensure that your blooms aren’t damaged by frost overnight.
The best advice we can give to new gardeners is that it is often best to JUST ASK. We are always happy to give advice to gardeners looking to grow healthy plants.