FAQs about growing dahlias in Seattle

Sometimes when I talk about dahlias I feel like the kid in the high school 90s movie who is trying to get all the other kids to try drugs. (“JUST TRY IT, TIMMY! YOU’LL HAVE FUN.”)

They're my favorite flower and so fun to grow. And I love encouraging others to try out this flower. Since Anne (from Candide Flowers) and I launched out dahlia tuber sale in February, we've been getting a lot of questions about growing dahlias in Seattle. 

I wanted to compile some of the more frequent FAQs here. If you have additional questions, please shoot me an email.

Can dahlias be planted in pots (or grow bags?)

Yup! Pick at least a 12” (heavy) pot or a 5-gallon grow bag. (You’ll need to water them a little extra through the hot season.)

Do dahlias come back year after year?

Yes — it depends on a few things that you can do to help overwinter them — but yes, our climate is excellent to overwinter dahlias in.

I am new to dahlias, how many should I grow?

This is a horrible question for me because my first year I grew like 50, which absolutely is not a reasonable number. (And this year I am growing over 200.)

I think a reasonable person would say grow three to five. (But I’m not a reasonable person so I say go wild.)

How much space do dahlias need?

12 inches (though you can give them more if you’d like.)

How do I plant them?

Check out this handy-dandy grow guide.

When should I plant them?

In Seattle, plant dahlias early April through mid-May. If you plant them later then that, they will be fine, but don’t expect to see blooms until late September/early October. The earlier you plant in April, the more flowers you will see earlier in the season.

How many blooms will a dahlia produce and when do they start blooming?

It depends on the variety, but if you keep snipping blooms two or three times a week, your plant will be more prolific. I’ve had dahlias bloom as early as mid-July bloom through early November (or first frost.)

I hope to add to this FAQ list, so shoot me an email with your ideas and questions.

Happy growing!

Stephanie

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