Time to Start Cool-Season Seeds Indoors!

While winter still lingers outside, something exciting is happening indoors: cool-season seed-starting time has arrived. Crops like broccoli, cabbage, kale, and leeks thrive in cooler weather, and getting them started indoors now gives them the strong, steady start they need for an early spring transplant.

For Canadian gardeners, these hardy vegetables are spring staples. They tolerate chilly temperatures, reward you with nutrient-dense harvests, and set the tone for a productive growing season. If you’re itching to get growing, this is the perfect moment to dig out your seed trays and begin.

Why Start Cool-Season Crops Indoors?

Cool-season vegetables are built for spring and early summer, but they still need time to establish before heading outdoors. Starting them indoors gives you control over timing and growing conditions — a huge advantage in Canada’s unpredictable spring weather.

Here’s why indoor sowing works so well:

Earlier harvests: Strong seedlings can be transplanted as soon as the soil is workable.
Better growth: Indoor starts avoid cold, wet soil that can slow or damage direct-sown seeds.
Efficient use of space: You can grow many seedlings in a small indoor area.
Stronger plants: Gradually acclimated seedlings are more resilient once planted outside.

By the time spring arrives, your plants are already well on their way.

What to Start Now

These vegetables love cool temperatures and benefit greatly from an indoor head start:

Broccoli: A spring favourite that performs best when it matures before summer heat.
Cabbage: Slow-growing and space-hungry, cabbage needs time to develop strong roots.
Kale: Cold-tolerant and incredibly nutritious, kale is one of the easiest cool-season crops to grow.
Leeks: Long-season vegetables that absolutely need an early start to reach full size.

You can also add cauliflower, Brussels sprouts, and onions to your cool-season seed list if space allows.

Seed-Starting Tips for Cool-Season Success

Cool-season crops are forgiving, but good technique makes a big difference.

Here’s how to set them up for success:

Use seed-starting mix: Light, sterile soil encourages healthy root development and prevents disease.
Sow at the right depth: Most brassica seeds only need a light covering of soil.
Keep temperatures moderate: Unlike peppers or tomatoes, these seeds germinate well at 15–21°C.
Provide bright light: As soon as seedlings emerge, give them strong light to prevent legginess.
Water consistently: Keep soil moist but never waterlogged.
Thin seedlings early: Give each plant space to grow strong and straight.

Once seedlings have a few true leaves, they’ll be ready for hardening off — gradually adjusting to outdoor conditions before transplanting.

Timing Is Everything

Cool-season crops can often be planted outside weeks before the last frost, depending on your region. That makes planning especially important. Starting seeds too late may push maturity into warmer weather, which can cause stress or poor yields.

Check your average last frost date and count backward using seed packet guidelines. A simple planting calendar or garden journal helps keep everything on track year after year.

Why Choose Canadian Seeds

When you buy Canadian-grown seeds, you’re choosing varieties adapted to our climate, daylight hours, and growing conditions. These seeds are selected for reliability, cold tolerance, and strong performance in shorter growing seasons.

Your local garden centre is the best place to find seeds that truly suit your region. Staff can also help you choose varieties based on your space, soil, and experience level — whether you’re growing in raised beds, containers, or a traditional veggie patch.

Supporting local seed producers also means supporting Canadian growers, pollinators, and biodiversity.

Let the Growing Begin

Starting cool-season vegetables indoors is one of the most satisfying ways to kick off the gardening year. With broccoli, cabbage, kale, and leeks already growing on your windowsill, spring feels closer — even if snow is still outside.

So fill those trays, label your rows, and enjoy the quiet joy of early growing. Grab your Canadian seeds at your local garden centre and give your veggie season the best possible start.