Seed Starting Guide and Calendar for Ontario

Sure, farm fresh veggies are great, but you know what’s even better? Garden fresh veggies from your own yard! But with complicated frost-date-dependant planting timelines on every seed packet, it can easily feel like you have to master Mother Nature before you’ll ever enjoy fresh flavour from your garden. Truth is, though, all you need is a calendar!

Here at Heeman’s, we like to make gardening a little easier for you, so we put together this handy seeding calendar just for Ontario to help you start your favourite veggies and flowers on time. Since a lot of fruits, veggies and flowers need to be started indoors in our region, we’ve stuck to some of the most popular ones to grow from seeds. After all, you wouldn’t want your whole house to be chock full of pots to transplant – that’s our job! Save your indoor space for the seedlings you love the most, and we’ll take care of the others until they’re ready to move in to your garden.

Click on any of the below Seeding Calendars to view larger or to save and print for easy reference!

February

In the dead of winter, when your garden’s still coated in a layer of snow so deep you could swim in it, I can guarantee the last thing on your mind is getting out in the garden. With spring just around the corner, though, (I know – hard to believe, right?) it’s time to get planning.

This is the perfect time to put together your list of must-haves and start picking up your supplies to get started – and get excited about spring. If you’re ambitious enough, you can even get a head start by starting some seeds inside!

March

Our last expected frost date here in Ontario is usually around the first week or two of May. So, plants that need to be started 6-8 weeks before then, like tomatoes and peppers, should get started now.

You can get peppers started indoors early in March, just keep them near a bright window while they’re germinating to keep them warm.

With tomatoes, most of them want to get started in late to mid-March, but make sure you stick to their variety’s schedule – starting them too early can leave you with a plant that’s as leggy and pale as a seasick supermodel. They don’t need light to germinate, just get them to a window once they start to sprout!

Toward the end of March, into early April, start nasturtium seeds indoors to get them ready for early-spring transplanting. Nasturtiums produce more blooms when transplanted in sunny areas with poor soil, so those areas that aren’t fertile enough for your veggies are perfect for these (edible!) flowers.

April

When April comes around, it’s a good time to get started on your broccoli, cauliflower, and celery seeds. Like a fine wine, these vegetables take time to mature, so give them a good start indoors now, so they’re ripe for the picking before the fall frost.

You’ll need rich soil to get your broccoli and cauliflower going, and lots of light for germination. You can transplant them after the last frost, but keep them in an extra week if you still feel a nip in the air, just to be safe.

For celery, poke your seeds into the soil lightly, but keep them close to the surface and shallow. Put some plastic on top to keep the moisture in and just let them be. Around mid-June, the temperatures will be perfect for you to pop those suckers in soil outside.

“Cucurbits grow quickly, so a 4–6 week head start in the growing season will have fresh flavours on your plates in no time!”

Cucurbits, like cucumber and zucchini, can get started around mid-April, too. They grow pretty quickly, so a 4-6 week head start in the growing season will have fresh flavours on your plates in no time! Keep them in a bright, warm place for successful germination.

While we may be seeking sunshine down south this time of year, salad greens, like lettuce, spinach, and kale, are quite comfortable in cool temperatures, so they can go straight in the ground earlier than other veggies. If you feel like starting them inside, though, now’s the time, just give them rich, moist soil and keep them cool (below 15℃) until they’re about 3” tall, then transplant them to the garden.

If broad beans are on your growing list this year, now’s the time to get these cold-lovers in the ground. Once the ground is workable, get them planted directly into the soil outside to enjoy a tasty harvest in the sunny summer.

Late into April, you can start moonflower seeds indoors in a warm and sunny spot. Moonflowers are heat-lovers that shouldn’t be transplanted until late spring, when the nights have begun to warm up. In return, you’ll be rewarded with their sweet scent during late summer nights on the patio.

May

April showers bring May flowers, but they also bring root vegetables, like beets, carrots, parsnips, radish, turnips, onions, and potatoes. When the soil is just thawed enough that the top inch isn’t cold to the touch, you can start direct seeding without worry.

Now that the ground is workable again, it’s also safe to direct seed quick-growing flowers and other vegetables outdoors. Sunflowers can be seeded directly from early to mid-month, as long as the risk of frost has passed. Morning glories grow quickly, and the seeds can be sown a couple of weeks after the last frost in a sunny place with well-drained soil. If you didn’t already start them inside, you can seed your beans, corn*, lettuce, kale, or any other early-season veggies directly into the ground.

*While corn can be direct-seeded in mid-May, it’s a tricky crop to grow for beginner or intermediate gardeners – simply because so many pests find it just as delicious as we do. Don’t worry, though, you can find the farm-fresh quality in our produce section here at Heeman’s – no pests required!

June to September

By early summer, most of the seeding action is as done as the Stanley Cup Finals. But, there are a few veggies that don’t mind a little summertime action. If you start your cauliflower for a second round about mid-June, you can enjoy another bounty later on in the summer. In August, you can throw some more carrots and onions in the ground again, too, for another round of reaping in the cooler late summer weather.

September is the last planting season of the year, and it’s the time to get your late fall harvests in the ground. Direct seed cold-lovers, like spinach and kale*, now for delicious delights right into winter.

Garlic bulbs can be planted underground in mid-October, where they’ll hang out until they’re ready for harvest the following summer.

*Just a note on kale: This frilly green can be planted this late in the year, but they will only continue to grow until the first frost. Frost makes the leaves a little sweeter, but it will also cut off your kale supply for the year. If you love cooking with kale, try planting it earlier in the spring to keep your salad bowl full from summer to late fall.

You don’t need to be a meteorologist to master seeding in your garden. All it takes is a simple month-by-month schedule to keep you on track!