Sweet Williams (Dianthus barbatus) are a total favorite for home gardeners, mostly because they show off their gorgeous blooms all summer long—from June straight through September. Sure, you can always grab some pre-grown containers at the local nursery, but there’s something so rewarding about growing them from scratch. Plus, they’re actually pretty easy to start from seed if you know a few simple tricks!
To Buy or to Collect?
The first thing you’ll need to decide is whether to buy a packet of seeds or harvest them yourself from existing plants. Here’s the deal: Sweet Williams come in a wild variety of colors. If you collect seeds from last year’s plants, you’re playing a bit of a color lottery—you never quite know what shade you’re going to get. If you have a specific color palette in mind for your garden, buying a fresh packet of seeds is the way to go to avoid any “floral surprises.”
Should You Start Them Indoors?
A common question I get is whether you should start these beauties indoors or sow them directly into the garden. Since Sweet Williams are hardy plants, they can handle the elements just fine. There’s really no need to baby them inside; you can sow them right into your flower beds without worrying about a little overnight frost. Once the spring temperatures level out, they usually sprout pretty quickly. Just keep in mind: they’re biennials, so they typically spend their first year growing leaves and won’t actually bloom until their second summer.
How to Sow Your Seeds
The sweet spot for planting is from late April through the end of May. Here’s my step-by-step guide to getting them started:
- Pick a spot in your garden that gets plenty of sunshine.
- Scatter the seeds thinly across the soil.
- Cover them with just a light dusting of dirt (don’t bury them too deep!).
- Keep the soil consistently moist, but make sure it’s not soaking wet—they don’t like “wet feet.”
If you want to move them to a different spot later on, just wait until the seedlings are about 4 to 6 inches tall before transplanting. Happy planting!
