Taking Dahlia Cuttings

blown_dry · 2023-02-04T23:34:14+00:00

Continuing from https://cubits.org/Dahlias/thread/view/92091/#end_of_thread

SteveM

I used to use the cheapo, cool-white fluorescent shop lights (from the big box stores) to root my cuttings but now I use the cheapo, cool-white LED shop lights (from the big box stores). The red spectrum isn't necessary for vegetative growth.

NCDahlia

I have my lights on a timer to turn on at 6 am and turn off at 10 pm. I do not use a heat mat (only for garden hard to germinate like peppers). I have 2 4-shelf, 16 tray light stands bought 10 years ago from "harris seed" probably is 3x what I paid back then with the inflation.

jistjul

NCDahlia Thanks! My lights are on a timer too. They come on at 6:30am and go out at 8:30pm

jistjul

SteveM Thank you! Lights are on 14 hours (on a timer) The temperature inside the dome (ambient air temp - not medium) is consistently 82 while lights are on. Humidity is between 50 and 60%.

SteveM

jistjul 82º @ 50% RH should be close to perfect. I don't worry about it being too hot until it gets about 85º or above but that is under my growing conditions. The old saying "There are as many ways to store dahlia tubers as there are dahlia growers." also applies to taking cuttings. I have killed many, many cuttings learning and improving on what works best in my case. If you experiment you will soon find what works best for your specific conditions. Keep us posted!

bloomhjelm

Speaking of a million different ways. Some friends have suggested using a syringe to inject rooting gel into a rooting cube, instead of dipping multiple cuttings in the same plop of rooting powder. I only have rooting powder. I would like to try this, and am considering mixing it with aloe vera to make a "gel" though instead of buying a whole new thing of IBA in a different form. I can't think of any downside to this except taking my own time.

ksc

After numerous little experiments I've come to the conclusion that dahlia cuttings root despite using gels/powders, I also found some rooting products actually hinder rooting. I think that stable conditions in the right zone are far more important for quick rooting.

Teddahlia

We stopped using rooting hormones well over 20 years ago. We grow about 1,000 cuttings per year. They are done in batches of 36. After 12 days under the lights a typical batch has about 30 rooted. I define rooted as seeing white roots at the bottom of the small pot. Sometimes a couple rot. Sometimes a few do not root and they go into the hospital ward for unrooted cuttings. Most of them root but a few are just duds. Usually I have 4 or 5 pots with two cuttings in them and so generally get a full 36 from each flat.
I do cuttings off of tubers for 80% of them. I always do some leaf cuttings and it is fun to get plants from split stems. However, they take an extra 2 weeks of growing to be the same size as tuber cuttings. I do not mix white cuttings with regular cuttings and they are rooted in the hospital ward.
Would rooting hormones improve our results? I bet the leaf cuttings may benefit while the tuber cuttings probably not much. My big concern is the fact that rooting hormones are chemicals and my son the chemist always says if you can avoid exposure to a chemical, you are better off. So we avoid using the rooting concoctions and I do not have roots growing from my fingers.

SteveM

Last year I rooted 50 Lady Nathalie cuttings with rooting hormone and 50 without. After 14 days in oasis, there was no noticeable difference with the % of rooted cuttings, number of roots, or length of roots. With this variety rooting hormone didn't seem to make any difference.
So, why do I still use rooting hormone on all of my cuttings even though any benefit is doubtful? Simply, the length of time it takes me to dip a cutting in rooting hormone allows me the time to wish "good luck" to every cutting. So, even though I doubt the value of using rooting hormone, I am positive that there is great benefit in talking to my cuttings.

bloomhjelm

I do believe that rooting hormone isn't purely necessary. My small batches of cuttings are a mix of insurance plant snips, tip cuttings from new plants from friends, and some tuber pulls, and my methods aren't always consistent. So it does feel a bit like a little extra well wishes more than anything.

I used to make a lot of cold process soap, and while fragrance oil isn't in itself necessarily dangerous, many of them do contain phthalates, and repeated small exposures over time are probably not a great idea.

A popular grower on Facebook posted a video of her cutting method which involves three to five different rooting substances. I am pretty sure most of these were different forms of IBA. She claimed roots in 2 to 5 days. If she does not use affiliate links to sell these products she for sure should. She's got the ginsu knives magic.

MissyWeitzel

SteveM how are the cuttings straight into soil doing?

SteveM

MissyWeitzel They're doing great, thanks for the heads up, and don't seem to be bothered by the 2" of rain wee had a few days ago. If I ever decide to go into the pot tuber biz this is the method I will use to root cuttings. I will use a slightly more porous mix (than the Sunshine #4) by adding perlite. For selling cuttings locally I will keep using oasis for now because there is no prep involved (mixing soil, washing and filling cells) and a block of oasis is easier to water consistently than individual soil/media cells. When I sell cuttings wholesale I don't care if the tuber eyes are buried in oasis.🙂

drewtheflorist

Tried with/without over the years and don't see much benefit to using hormones to root dahlias. Some plants, Ficus in particular, have a delay in growth caused by hormones. Ficus will root fine with IBA but will sit there for a month or more until the hormone "gets out of it's system" , where as a newly rooted cutting of ficus sans-hormone will start new growth immediately after rooting. Fall cuttings of Aggie White

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