When to Plant in Ontario

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Living in Ontario, we are lucky that we get four distinct seasons: spring, summer, fall and winter. But sometimes that can make being a gardener a little tricky. Here are some tips for planting in Southern Ontario’s climate!

Annuals

Annuals can be delicate and won’t tolerate any frost, so they should be planted after the last frost – usually around the May 2-4 weekend in Ontario. Some annuals can be started indoors up to 6 weeks before the last frost (mid-April to the end of April).

If you get annuals growing early, once they have started to grow leaves and vegetate you can make them hardier by putting them outside during the day and bringing them inside at night. By the end of May, they’ll be ready to plant in the ground and will already be fairly substantial — so you’ll have flowers earlier!

Great Annual Species for Ontario

Certain annuals are ideally suited for the varied climate of Ontario. Why not try some of these annuals in your garden this spring?

  • Begonias
  • Dahlias
  • Fuchsia
  • Geraniums
  • Impatiens
  • Marigolds
  • Pansies
  • Snapdragons
  • Violas
 
 

Flower Bulbs

When to plant flower bulbs in OntarioIf you’re planting flower bulbs in your garden, everything will depend on whether you have selected spring or fall bulbs. For spring-planted bulbs, make sure to plant these after the last chance of frost has passed. For fall-planted bulbs, plant these before the ground freezes so they have time to take root to flower in the spring.

If you forget to plants bulbs in the fall, don’t wait until next yet! Plant them as soon as the ground thaws enough in the spring. Bulbs are living plants and they will dry up if they do not nourishment after a certain amount of time. Some of them may not successfully bloom, but you may get lucky with a few of them!

Common Spring-Planted Bulbs

  • Begonias
  • Caladium
  • Dahlias
  • Freesia
  • Gladiolus
  • Lilies
  • Sorrels

Common Fall-Planted Bulbs

  • Buttercups
  • Crocuses
  • Daffodils
  • Hyacinths
  • Irises
  • Snowdrops
  • Tulips

Perennials

Perennials prefer to be planted at times when the ground is moist and warm. They can be planted in the early fall (September), but they prefer to be planted in the late spring or early summer in Ontario, after the ground has thawed (May to June).

In the fall and spring, consider dividing perennials you already have. For example, if a group of plants is getting too big, you can divide it into two. They tend to grow better this way, and you can increase the number of plants you have.

In the early spring, start identifying plants that have started to seed themselves, like poppies. Identifying them early means you can move them to pots until they get stronger, or move them to another area of your garden where you’d prefer to have them. As long as the soil isn’t frozen, you can move things easily, and it’s great to do it before it gets too hot!

Best Perennials to Plant in Ontario

  • Black-eyed susans
  • Foxgloves
  • Garden phlox
  • Hostas
  • Hydrangeas
  • Lobelias
  • Peonies
  • Poppies
  • Roses
 
 

Vegetables

When to plant vegetables in OntarioLate spring is the optimal time to be planting vegetable seeds in Canada, but some vegetables are hardier and will survive better early in the season. These species are called ‘cool-season vegetables’. Most cool-season varieties will not be affected by a light frost, so you can safely plant them in May or June.

Certain species can be started indoors by seed in the winter and moved outdoors in the summer, such as parsley, peppers, onions, and asparagus.

Common Cool-Season Vegetables

  • Asparagus
  • Beans
  • Beets
  • Broccoli
  • Brussel sprouts
  • Cabbage
  • Carrots
  • Cauliflower
  • Garlic
  • Kale
  • Lettuce
  • Onions
  • Parsley
  • Peas
  • Potatoes
  • Radishes
  • Spinach
  • Turnips

See below for a detailed vegetable planting chart for Southern Ontario, courtesy of West Coast Seeds.

Vegetable Planting Chart from West Coast Seeds

Image Credit: West Coast Seeds

Trees & Shrubs 

When to plant trees or shrubs in OntarioTrees and shrubs should be planted in the fall, from the end of August to mid-October and sometimes even later — depending on the weather each year. This will give them time to establish their root system in the still-warm soil.

The spring is not the best time for planting trees or shrubs because the wet ground makes it more difficult for newly planted trees to take hold. Trees and shrubs will need dryer groundfor proper root growth. There are some exceptions to the general rule, especially for bare roots, but fall is generally the best time for transferring any potted shrubs or trees to the ground.

Looking for soil or mulch to help your garden grow? Check out the wide selection of products at Dirt Cheap to get started with planting in Ontario.

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