Dahlias have never been cheap, but in recent times they’ve grown particularly expensive. Tubers can be difficult to store, and growing your dahlia collection can be a terribly expensive and painstaking process. While I can’t make it totally cheap for you, taking cuttings from dahlia tubers in the winter is one of the more economical (and simplest) ways to grow your dahlia collection, along with dividing your tubers.
In a short growing season, it’s especially challenging to take dahlia cuttings and have them produce tubers. I’ve tried this for a couple of years with varying results, and I now feel confident in my timing and am willing to share those successes and failures with you.
If you want to learn more about growing dahlias from cuttings, read on!
More of a visual learner? Check out the short below:
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How to Take Dahlia Cuttings
When harvesting dahlia cuttings, take your cutting as close to the tuber as you can. You can rip them off or use snips. I know ripping them off isn’t recommended, but I’ve found it works just fine.
Here are the step-by-step instructions for taking dahlia cuttings:
- Take dahlia tubers out of storage & divide them if you have not already
- Put tubers under grow lights for 12-16 hours a day (16 hours is best)
- Once the dahlia tubers eye up and the green bits look cuttable, cut them
- Dip your cuttings in rooting hormone & put them in potting soil
- Care for your new dahlia cuttings like you would any other seedling
Related: How to Overwinter Dahlias in Cold Climates
Where do you get rooting hormone? And do you have to use it?
Rooting hormone comes in gel or powder. I prefer the gel because you don’t have to do the extra step of mixing. I was initially scared about using rooting hormone, and I put off doing it for two years because it felt too complicated. However, when I actually bought the little jar and realized how simple it was, I didn’t understand why I had been afraid to do it.
So, how do you use rooting hormone? Open the lid, dunk the cutting into the hormone, and put it in the soil. You really don’t have to do anything more special or complicated than that. You can get your rooting hormone from any garden centre that is not a big box store, or you can find it online.
Related: How to Grow Dahlias in a Short Growing Season and Cold Climate
Can you propagate dahlia cuttings with water?
Short answer, yes. But it doesn’t seem to be as successful as using the rooting hormone. When I tried propagating dahlia cuttings in water, I found they took about 2-3 weeks to root, but when I transferred them into soil, about half of them flopped over and eventually died. They never perked back up, and I don’t know why.
If you choose to use the water method, you’ll want to take a cutting about 4 inches long, give or take. Make sure that your jar of cuttings is placed on a windowsill that gets a lot of light (not north-facing) or is under a grow light.
How big do the cuttings have to be?
Despite the typical advice you will find online (if you’ve read a few posts on the subject besides this one), I have found that taking cuttings when they are about 2 inches tall works best. When I’ve taken cuttings at about 4 inches (which is the more typical advice), they’ve gone into shock or died, and they generally haven’t worked as well for me. I realize this is not standard advice, so take it with a grain of salt.
Related: How to Keep Thrips Away from Your Dahlias
When do you need to wake up your tubers to take cuttings?
You can wake up your tubers in mid-February and get them under grow lights. You have until approximately the end of March to take cuttings, but anything later than that, and I find that they will not produce usable tubers. If you don’t care about getting usable tubers from your cuttings, at least in your short growing season, you can wake up your tubers as late as Mid-april.
Related: Do This One Thing to See Your Dahlias Bloom!
Can you grow tubers from cuttings?
Short answer, yes. But it might not be as perfect as you’d hoped.
You have to make sure you start your dahlia cuttings early to get tubers. To successfully get tubers from cuttings, you’ll need to take them no later than the end of March. Any cuttings you take after that will likely not produce tubers, and if they do, the tubers will likely be too small to do anything with.
Last year, I found that my dahlias grown from cuttings produced only mother tubers, with few to no baby tubers attached.
Will your dahlia cuttings produce usable flowers?
Yes, but they may not be as prolific as a dahlia plant with tubers attached.
Related: Swoon-Worthy Dahlia Varieties for your Cut Flower Garden
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Anne