Cuttings and Clones: Optimal Environment

I wanted to gather some thoughts on this as everyone does it at least a little differently. Here are some questions to answer that will hopefully allow us to create better industry standards and all become better growers. What have you found to work best?

  1. Light: What ppfd or ppf have you all found to work best for rooting cuttings? What about specific spectrum? What about light cycle?

  2. Total Dissolved Solids (TDS): For those in aeroponics (or any type of reservoir), what ppm have you found most effective? When do you increase ppm? What increments?

  3. ***Organic Cloning: Is anyone doing this with consistent results that compete with synthetic rooting hormones (over 90% success rate)? What are your nutrient recipes or other techniques? IBA is technically a pesticide and must be listed on the label of your consumer product. I get the feeling a lot of people are claiming to be organic, but are still using rooting hormones… And leaving it off their labels…

  4. Air and water/plug temperature: What have you found to be ideal temperatures for your cuttings? Do you keep the rooting area at a separate temperature from the foliage?

***This is the topic I am most interested in. We have been performing a number of trials with mixed success. Factors that are obviously important are mother health and cloning environment, but I think it’s becoming more apparent to us that light spectrum and intensity in both the mother area and over the cuttings is a more complex topic worthy of discussion.

The biggest difference we have noticed that improved success (assuming great mother health) was using cuttings from a mother under a MH light, where intensity was higher than under our typical t5 setup. The soil was also somewhat different, so I can’t leave that out as a variable.

Being careful not to over water the plugs or pellets has shown to be very important, which is a finicky business due to naturally changing environment, making it difficult to write a standard SOP that all employees can easily follow. Any suggestions about moisture consistency?

We have tried a number of approaches involving supplements like aloe, Ful Power, Azos, etc. Soluble silica is not truly organic so we haven’t bothered with that. I want to try compost tea or leachate next as it has light nutrient value as well as microbes to make it plant-available. Or rooting straight into a worm casting and aeration mix. Anyone with experiences?

I’d be happy to talk details and trade information with anyone interested! We are really braving new territory here I believe. I don’t think there are many (if any) commercial propagation industries that clone organically (except for maybe succulents). It’s a challenge to be sure as it’s quite an amazing natural process.


Cody, this is one of the best discussions ever posted on our forum since we launched. Thank you for thoughtfully leading the discussion in the right direction. Together, with discussions exactly like this one, we can help strengthen the overall standard of growing practices as an industry. I commend you and hope that other members will follow in your direction. Thank you.


Let me address some of your questions on how I would approach the matter, but by all means I would like to encourage some discussion on your talking points:

I’ll answer your questions in the numerical order in which they were first posed:

  1. When cloning, I have found this is the only time in the plant’s life cycle that the plant system doesn’t require very intense light. I use low wattage LED’s when cloning. They run at 11 watts and are full spectrum. I get clones within 10 days every time with 99% success. As long as the temp and RH stay constant, roots happen!
  1. I rarely run aero systems these days, but I have in the past so I can speak on the subject. I would keep the PPMs around the 100 range and not too much higher. These cuttings need very little to produce roots, and you surely do not want to burn them with a high PPM!

  2. Aloe vera can be an effective rooting hormone without utilizing the indole-3 butyric acid (IBA). I’ve never know any ill-effects in human health from using IBA (I still use Dip-n-gro, folks), however I understand the consumer fear. Aloe works, it just may take a little longer to produce roots; also aloe should be be consistent with all required organic protocols.

  3. If there’s one word I might recommend here: CONSISTENCY! I keep the root temp the same as the foliage temp and I see perfect success every time. Any thoughts on this, growers?

I can talk at great length about staff issues related to cloning (truly, I could create a thread of biblical proportions about THAT issue). I always start new staff in the propagation area of the facility. I find this area of plant growth sets up the foundation for understanding the entire plant system as a whole. Also, I always like to set up staff for success: everybody who worked on my team can say he or she made 2000 clones in his or her first week of work. Now that’s an accomplishment!

I’d be interested to know how the organic cloning protocols are progressing. Where are you finding the most success?


Interesting old topic .
I have done experiments/trials about all 4 topics you have listed .

  1. Regarding rooting success you will not see difference between , i have tested on 50 ppfd , 100 ppfd and 150 ppfd , i had very close results . The foliage quality is definitely the best on 50 ppfd , the cuttings grown on 150 ppfd were burn and yellow . I keep on 50 ppfd for 24h , another important thing is DLI . The ppfd depends from the DLI .

2.Here i have play with 0 EC , 1EC , 2EC . I use 1EC for best (most fast) rooting success , for best foliage appearance 2 EC with delay of 4-5 days . If you plan selling clones i will go with 2EC , but you will lose few days .

3.This will stay secret , i will just say there is one product which is gold standard in the cannabis industry for taking cuttings and it hurt the clones a lot , but for some reasons people are using bc is good advertised .

  1. If using heat mats , root temperature 72-78 with canopy temperature 72-74 . If not using heat mats canopy temperature of 80 . Temperature is main factor in rooting success !

When i talk about best and success i thing on rooting success in 2 weeks ! The rooting success in general it will be 100% if you did not hurt them or mechanically injured them .There is no cutting that will not root sooner or later ! Talking about rooting success absolutely depends from the genetic , in 10 days i have strains with 90+ success , another strain with 0% !

The biggest killers of cutting are humidity domes and spraying , people see that S-shape of cuttings and start spraying or increasing humidity . The S-shape is very common thing , and is not result of low humidity or light intensity . Its result of another very common practice again gold standard in the cannabis industry that is totally wrong .

The worst rooting success rate is in the cannabis industry and that is very close related with the cannabis as expensive crop and using methods , practices and supplements that are totally unfamiliar for the horticulture , that actually harm plants.

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TBF this is done with virtually every USDA Organic crop that is grown from cuttings/clones (sweet potatoes are a rare exception). The propagation department is typically not certified organic but that is not important for organic certification unless certified organic clones (they’re commonly called “liners” in the industry) are widely available. I managed a certified organic tea farm that produced all its tea plants from clones. The propagation greenhouse was not certified organic, but the fields were.

But it’s not disingenuous at all. I mean, where does it stop? Even if the cuttings were rooted organically, were the mother plants (called “stock plants” in the industry) managed organically, too? How about the seeds they were originally grown from?

These days there are even certified organic feminized seeds; they do it with cucumbers too. I guarantee they aren’t treating the pollinators organically but then, they aren’t the plants that are producing the seeds.

But you might check out this recent study on vegetative propagation of Cannabis, the most comprehensive such study I am aware of for decades: Canadian Science Publishing

They used Jiffy pellets soaked in

a solution of ‘Spurt’liquid organic
fertilizer [2.0–0.0–0.83 (N–P–K); EZ-GRO Inc.] at a rate that
supplied 123 mg N L−1


From days 0 to 4 after cuttings were placed
in the substrate (DAP), RH was maintained at 95% (±1.3%),
reduced to 80% (±1.3%) for 5–8 DAP, and to 60% (±1.5%)
for 9–12 DAP. Temperature was maintained at 24 °C
(±0.04 °C) (day/night) for the entire period. Fluorescent
lighting (Philips Lighting) was used to maintain an 18 h
photoperiod. Photosynthetically active radiation at
the canopy level was maintained at 50 μmol m−2 s−1
(±0.6 μmol m−2 s−1) for 0 –4 DAP, 80 μmol m−2 s−1
(±0.7 μmol m−2 s−1) for 5 –8 DAP, and 115 μmol m−2 s−1
(±0.5 μmol m−2 s−1) for 9–12 DAP.

There is lots more useful information in that publication, too :grinning:

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