How and When to Start a Vegetable Garden in Ontario

Living in Ontario means dealing with fluctuating temperatures year-round, which can be a challenge for novice gardeners. But you can still have your own successful vegetable garden if you plan it right and take regular care of your plants. Here’s a starter’s guide to starting a vegetable garden in Ontario.

Size and Location

If you’re new to growing your own food, it’s best to start small. The bigger the garden, the more maintenance it’ll take to keep it healthy. We recommend choosing an area in your yard between 3 and 5 metres square. You can always expand it next year if you find you have a knack for gardening!

Choose a spot where the ground is level to ensure water doesn’t pool at one area of the garden. Vegetables need at least six hours of sun a day, so choose a spot on the southern or western side of your house that gets plenty of light.

It helps if you can pick an area close to your faucet. This will reduce the time it takes to water your garden.

Preparing the Soil

Before you start planting, prepare the soil by raking out stones and pulling weeds. The best soil for gardening is soft, loamy, and rich in nutrients. If you’re planning an organic garden, be sure your soil is organic as well.

Choosing Plants

Ontario has a short growing season, but there are still many vegetables that do well in our climate. Easy beginner plants include tomatoes, carrots, zucchini, chard, radishes, peppers, cabbage, lettuce and beets. Pick your favourites, but be sure to have a mind for companion planting. Not all vegetables do well when planted side-by-side.

As a beginner, one of the decisions you’ll have to make is whether to start from seeds or seedlings. Seeds are less expensive, but they can be a challenge to get going. Buying plants from a nursery costs more, but it gives you a leg-up by eliminating the trouble of germinating the seeds. Planting seedlings also lets you start later in the growing season; seeds need to be in the ground as early as spring.

When to Plant

Here in Ontario, the weather is far too volatile to set strict planting dates. Instead, it’s best to pay attention to the soil temperature and frost when determining when to plant.

Most seeds should be planted a certain number of week before or after the ‘last frost date’, meaning the date after which there’s only a 10% chance of a hard frost. That falls mid to late May for most of southern Ontario, but it can vary year-to-year. The soil temperature can also fluctuate with the weather.

This is another reason seedlings are an easier option for newbies!


When it’s time to plant, mark your rows with stakes to indicate what kind of vegetable is there and when it was planted. Follow the instructions on the seed packet or card that came with the seedling; otherwise, you can find guidance on how to plant different vegetables on the Farmer’s Almanac site.

Be sure to plant taller plants on the northern and eastern side of your garden plot. Otherwise, they could shade the shorter plants and reduce the amount of sun they get.

If you’re working with seedlings, choose an overcast day but dry day on which to plant. This will reduce the stress on the plants.


You should start weeding your garden right away, as they compete with your plants for nutrients and growing space. If you let them grow too much, you risk damaging the roots of your vegetables when you pull the weeds out. Set a regular schedule of once or twice a week, depending on your weed situation.

Weeding is easier on days when the soil is moist, such as the day after rain or watering.


Most vegetables need 3-4cm of water each week to thrive. You must water your plants several times a week if it doesn’t rain, especially when your plants are young. Small plants have shallow roots, so they can’t reach the moist soil further below the surface.

Always water in the morning or early afternoon. Watering later in the day means the leaves will be wet overnight, which makes them more susceptible to pests and fungal disease.


Mulch is a soil cover made from organic material like hay, leaves, peat moss, or grass clipping, Once your plants have reached a height of 10cm or more, you should lay mulch around them. This helps to prevent weeds and cools the soil down to conserve moisture.