From Seed to Seed Saving: How I Grow Calendula in Southern Ontario

Calendula harvest days are my favourite! Messy hands, full baskets, and the promise of what’s next.

If you received calendula seeds from me — welcome. I’m really glad they’ve found their way into your hands.

Calendula has been one of the most rewarding plants I’ve ever grown. It’s resilient, generous, unfussy, and blooms for months on end — often far longer than you’d expect. It’s also one of those plants that quietly builds your confidence as a gardener, whether you’re brand new or well seasoned.

I wanted to share exactly how I grow calendula here in southern Ontario, from the moment the seeds go into the soil to saving seed at the end of the season. My hope is that you can use this as a flexible guide and adjust it for your own garden, climate, and growing zone.

Why Calendula Grows So Well Here

Calendula really shines in our region. Although it’s typically grown as an annual, it’s exceptionally well suited to southern Ontario’s climate and performs beautifully with very little intervention.

I garden in Zone 6a–6b, where calendula thrives in full sun and doesn’t demand perfect conditions. If you’re gardening somewhere else, you can absolutely use this as a reference — just adjust your timing based on your local last frost date.

One of the things I appreciate most about calendula is how forgiving it is. It doesn’t punish you for being slightly early, slightly late, or slightly imperfect. (Which makes it a joy to grow.)

When I Plant Calendula (And How You Can Adjust)

Over the years, I’ve tried both direct sowing and starting seeds indoors. These days, I almost always direct sow — not because it’s superior, but because it’s simpler and works just as well.

Direct sowing (my preferred method)

I direct sow calendula seeds in late April to early May, once the soil is workable. There’s no need to wait for pristine spring conditions — calendula can handle a bit of unpredictability.

Starting seeds indoors (optional)

If you prefer to start seeds inside, early to mid-April works well. Any earlier than that and you’ll likely need to up-pot, which adds an extra step without much benefit.

Fun fact: I actually ran this as a small experiment in my own garden, planting some calendula indoors and some directly in the ground. The result? Both methods produced equally strong plants and abundant blooms. So it really comes down to personal preference.

Where you'll find me most days in the summer: tending to my calendula garden

How I Direct Sow Calendula Seeds

When I direct sow, this is exactly how I do it — no trays, no fuss, no overthinking. First, I choose a sunny spot. Full sun is ideal, though calendula will tolerate a bit of flexibility.

I lightly amend the soil with:

• A small amount of mushroom compost

• A small amount of worm compost

I gently blend this into the top layer of soil, broadcast the seeds by scattering them freely, cover them lightly (they don’t need much), and water gently.

That’s it!

Calendula doesn’t like being babied too much. In my experience, the less complicated you make it, the happier it is.

How Long Calendula Blooms

This is where calendula really earns its keep.

In my garden, blooms usually begin in June and continue right through October — and in some years, even into November. Last season, I had calendula still blooming with snow on the ground. (And yes, I took a photo. I needed proof!)

Proof that calendula is hardy enough to thrive in Ontario!

The key thing to know is this: the more you pick, the more it blooms. Regular harvesting encourages the plant to keep producing flowers, making it one of the most generous bloomers in the garden.

How I Save Calendula Seeds For Next Season

Seed saving usually begins around September, once the flowers have fully finished and the seed heads have dried on the plant.

You’ll know the seeds are ready when:

✅ The seed heads are very dry

    ✅ They come off the plant easily

   ✅ The seeds look like tiny worms — or, as some people say, little seahorses

What do you see? Worms or seahorses?

Once they’re ready, this is my process:

1. Harvest only fully dry seed heads

2. Remove the seeds and spread them out in a foil pan

3. Leave them in the garage for several days to ensure they’re completely dry

4. Transfer to an airtight container

5. Store in a cool, dry place over winter

Dry seeds are essential — moisture is the enemy here. Taking a bit of extra time at this stage makes all the difference.

Why Calendula Will Always Have a Place in My Garden

Calendula earns its spot every single year.

It’s easy to grow, generous with blooms, flowers for an impressively long time, and is incredibly simple to save seed from. Beyond that, it’s deeply satisfying to work with — a plant that's incredibly versatile and gives back far more than it asks.

It’s the kind of flower that quietly becomes part of your rhythm, season after season.

From seed to skincare. That's my philosophy.

Let’s Grow This Together

If you received calendula seeds from me, I would absolutely love to see them growing in your garden.

As the season unfolds, feel free to send me a DM on Instagram or email me photos of your calendula in bloom. In the fall, I’ll be creating a photo collage featuring calendula grown from the seeds I shared — a small celebration of how far these little seeds traveled and the gardens they became part of.

There’s something really special about seeing the same plant growing in so many different places.  And you’re officially part of this plant’s ongoing story now!