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 simple) ways to grow your dahlia collection, in addition to 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!
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 is not the recommended thing to do, but I’ve found that 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 how I could have 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 with water, I found that I would get roots after about 2-3 weeks, but when I transferred those cutting into the soil it seemed like 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 that is about 4 inches in length, 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.
P.S. If you are an aspiring farmer florist, check out my course Backyard Business where I break down this and other flower farming tips in written and video format.
How big do the cuttings have to be?
Despite the typical advice you will find on the internet (if you’ve read a few other posts other than this one on the subject), I have found that taking cuttings when they are about two 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 generally didn’t work 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 get cuttings from them?
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.
Want to learn more about waking up dahlia tubers? Check out this video:
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 in order to get tubers. To successfully get tubers from cuttings you’ll need to make sure you take your cuttings 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 only grew mother tubers with little to no baby tubers attached to them.
Will your dahlia cuttings produce usable flowers?
Yes, but they may not be as prolific as a dahlia plant that has tubers attached to it.
Related: Swoon-Worthy Dahlia Varieties for your Cut Flower Garden
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