How to Grow Dahlias in Pots
Erin’s gorgeous dahlias she grew in pots on her front porch.
March 7, 2024
My dear friend, Erin Maciejewski, is a wizard when it comes to growing gorgeous dahlias in pots. Since 2016, she has successfully planted dahlia tubers in all types of containers, from traditional flower pots to wooden wine-barrel type planters, to incredible effect.
As a dahlia farmer, I am frequently asked the best practices for growing dahlias in pots. I can give all the advice in the world that seems right, but truthfully, I grow all of my dahlia tubers in the ground and I don’t have first-hand experience growing dahlias in containers.
So I thought it would be fun to interview Erin about what she does to grow exceptional dahlias in pots on her full-sun front porch in Williamsville, NY (Zone 6b). I hope you learn what you need to know from our chatter!
At the end of this conversation, I’ll share a list of pots & containers appropriate for planting dahlias in, based on Erin’s advice!
Products mentioned in this post:
me (Fran): so Erin, tell me why you keep coming back to dahlias year after year. you must love them.
ERIN: Oh, yes! I started growing dahlias in 2016. I wanted something that I could grow in pots because we were in an apartment. I wanted flowers for in later summer to use for my wedding, and dahlias are so pretty. And I kept growing dahlias ever since because even in the pots they were successful! I was able to take the bulbs and keep them safe over winter and replant them the next year. And then I found you and kept buying your bulbs for the past couple years.
fran: What kind of pots do you use to grow dahlias — what size and materials?
ERIN: The pots I’m most successful growing dahlias in are wooden barrels, I think because of the size and drainage. I put bigger tubers, or more tubers, in the really big barrels that are 24”x24” wide. I have a concrete front porch, which holds heat and keeps the pots going longer into the season as opposed to placing the pots on the ground.
Visit our Amazon Storefront Here to see a list of great pots and planters for growing dahlias.
Fran: What’s your dahlia tuber spacing in pots? How many dahlia tubers per pot?
In the big 24”x24” round wooden barrel pots, I plant 3 tubers about a foot apart, a few inches from the edge of the pot.
In 18” x 18” square pots, I plant 2 tubers per pot of varieties that create smaller bulbs. I try not to put big ones with big ones. I put 2, maybe 3 of biggest ones in the biggest pots.
Fran: Right, because not all dahlia tubers produce the same size tubers. Some get massive!
fran: Do you do anything to prepare the soil in your pots?
I add brand new potting soil and mix it with compost; a 50-50 blend. At the end of the year, I empty the soil out of the pots and add that used soil to the compost pile.
fran: Ok, and you make your own compost.
I do make my own, and if I need more, I’ll buy some if I need it (here is good bagged compost). I have already produced several gallons of compost from my own scraps this year using my new Lomi machine. It produces a few cups of compost when the whole machine is full of scraps and it takes just a few days. I have coworkers that save their scraps for me at lunch and I take them home and make compost.
Fran: Wow, talk about resourceful!
fran: do you add fertilizer to your dahlias during the season at all?
I add more compost to the tops of the pots. If the dahlias start to look like they’re waning, that’s when I top off with the compost. But I’m using big pots with new soil so I generally don’t need to add anything during the year if I have a 50% mix of fresh compost mixed in.
Fran: How do you decide your timing for planting dahlia tubers in pots?
I usually look obsessively into the 10-day forecast and when it starts trending into the 40s for lows, then I prep the pots with new soil and compost, and plant the tubers at that time. One year I was too antsy and covered them with greenhouse plastic when it got too cold, but I wouldn’t bother taking that risk again.
Fran: So you don’t even wait to plant until it’s 60 degrees?
No, I just plant out when it’s looking like consistently low 40s without any last chance of freezing.
Fran: What’s your watering routine? Do you have a sprinkler or drip watering setup?
I do hand water everyday and it takes about 15 minutes everyday but I enjoy doing it. It’s like a mental health break! If it’s sunny everyday, I don’t worry about over watering the pots. I’ve skipped some days but they do better when I water every single day, especially when it’s consistently sunny.
Fran: Do you plant any in your backyard in the ground? (erin also has an amazing veggie garden in her backyard)
Nope. All my dahlias are in pots. I just feel like they grow so well in the pots that I don’t need to add them to the ground. I feel if they were in the ground, I wouldn’t be as attentive to them as I am on my front porch.
Fran: Do you cut the flowers and bring inside or just enjoy on the plant?
I cut them. I enjoy on the plant as long as I can, then cut them once they’re fully open and bring to enjoy inside.
Fran: Dahlias don’t open anymore after you cut them, so that’s perfect timing.
I cut them constantly and give them to friends and coworkers. I save glass dressing bottles and milk bottles and bring them to people as homegrown recycled gifts.
Fran: Flowers are our love language!
fran: Do you have any favorite dahlia varieties for pots?
I love the Cafe Au Laits, and I had a ton of big pink ones that are shaped exactly like the Cafes.
Fran: Oh, those are Cafe au Lait! They range from khaki colored to pinky blush.
I am also obsessed with the gigantic magenta one (Penhill Dark Monarch)… it’s my Facebook profile picture.
Fran: Haha, I love that. What do you do with your pots at the end of the year? Walk me through your process.
The two biggest wooden barrel pots stay out on the front porch because they’re so heavy, but I take out as much of the soil as I can and add it to the compost pile. The other pots, I empty completely and store them in the garage. The following year, I’ll pull the pots out and refill with the 50-50 new soil and compost blend.
Fran: So are you saving the tubers or just composting them?
I try to save them every year, but it’s hard. I try to pick a day after frost that’s sunny, and I lay them out on the driveway to let them dry off a bit, and pack them in wood chips. Some survive, some dry out and some rot, but I try! Any I have in excess I gift to friends and family who want to try growing them.
Fran: I love that we share this love of dahlias together. Thanks, friend.
End of conversation.
key takeaways from Erin’s advice on growing dahlias in planters:
Plant dahlias in containers that are at least 12” deep and 16” wide. The bigger the pot, the better.
Each dahlia tuber needs 12”x12”x12” of space to grow well. Don’t plant too many dahlia tubers in one pot!
Plant once all danger of freezing has left the forecast. Pots heat up quicker than the ground, so if properly cared for, you might get earlier blooms!
Replace the soil and add new compost every Spring.
Water everyday (you can set up a soaker hose on a timer to make this easier).
Perfect Pots and Planters for Growing Gorgeous, Productive Dahlias…
Click here or on the photo below!
