At the rate we can safely use chlorine without damaging plant roots, I’m unaware if it will deactivate the infectivity of viroids or viruses. Maybe it can, but I haven’t seen data to the point. Because of the damaging effects of chlorine on roots, even at low use rates, I use UV-C to treat irrigation solutions in drain-to-waste systems, so the solution from the batch tank is sterilized before it reaches the plants. I don’t know if UV-C can deactivate viroids/virsuses, but a Google Scholar search should be able to answer that question. UV-C is a must in recirculating systems, IMO.
That’s what I do, too. All coco pots are raised off the trays, and the same goes for Rockwool blocks. I do it primarily to prevent over-watering downstream plants (so they’re not absorbing run-off from upstream plants). But also to reduce the chance of root rot and algae cross-contamination and now, HLVd cross-contamination.
The max flow rate depends upon the size of the UV lamp, chamber, and solution turbidity. @danielfp provides target values for UV-C disinfection, and you would ask the supplier of the UV system what flow rates achieve the target values.
He also discusses many other methods of distinction, including chemicals. Aside from UV-C treatment of the batch tank’s solution during irrigation, I plan to test an iodine stock tank. So that I can use it to kill Pythium root rot without affecting the roots (adding it to my nutrient solution).
Thanks! I considered something like that, but I worry about affecting water flow because they sit on the tray (rather than raised off the tray a bit). Maybe placing 1/2" PVC lengthwise (parallel to the water flow) under those would work well.
Suggests to me that If the change in secondary metabolites is caused by the pathogen, calling it a “symptom” would be ok with the author of the above passage
Metabolomics wasn’t a thing, now it is.
That changes how close one needs to look to define asymptotic.
Revisiting the definitions as the science progresses is just how this works.
As I noted earlier, the research I have reviewed from this century, the last decade, and the last two years doesn’t list secondary metabolite changes as symptoms. Nor does the effect on secondary metabolites meet the symptom definition in plant pathology. And there are similar examples in medcine, where not all disease effects are symptoms (ground-glass lung in COVID-infected persons).
The most telling aspect is that none of the many studies on HLVd and other viroids and viruses affecting hops and cannabis (or other plants) list the viroid’s effect on terpenes as a symptom. None of them. They all repeatedly mention the effect on terpenes and the disease symptoms, but none of them suggest that the effect (affecting terpenes) is a symptom. And that includes studies from 2021 and 2022.
However, I found one study that suggests significantly reduced alpha acids in hops is a symptom of viroid infection. But it’s important to note that comparing the alpha acid content of an infected plant to that of a non-infected plant is far more straightforward than comparing terpene concentrations (which are not all decreased). Especially considering there are hundreds of terpenes, and their production is more sensitive to a myriad of stressors than alpha acid. So, this study’s use of reduction in AA as a symptom doesn’t apply to the use of terpenes as a symptom (reduction of some and an increase of others). Overall, because this is the only study I found with the use of AA as a symptom, it’s an outlier and probably shouldn’t be given much weight: Characterization of a new viroid strain from hops: evidence for viroid speciation by isolation in different host species
Science also works by accepting when you don’t have evidence supporting your position and abandoning a lost cause.
I have used chlorine in the past (low pH so it’s mostly hypochlorous acid), as well as chlorine dioxide, which both work as a disinfectant when used appropriately. But they are also oxidizers, so they are not ideal from a root health perspective, although their use is absolutely better than infected roots.
I use rockwool and coco, at home I mix it right into my res, at my shop I’ve got a orp controller connected to a dosing pump in my ro reservoir to make sure my water is always sterile.
You mean besides my base nutrients? I don’t want to go off topic but I also use, agt50, kelp, silica, aloe (since I bought a bunch I add in my foliar).
scalpels cut into the cells. its better to break the cells between each cell wall and less shit gets into it.= hippies with dirty fingers plucking is maybe cleaner than scalpels.
Me too. Means I learned something. Only decent reason for spending time in these meat suits imo.
Once taking a full mRNA expression profile becomes routine when you visit your GP, I suspect more folks will consider specific combinations of misexpressed genes as “symptoms” rather than merely “diagnostic”.
UV-C causes oxides (like hydroxyl radicals) to form in the nutrient soltuion. The oxides destabilize and degrade Fe chelators, releasing Fe(III) (ferric iron) into the solution. Fe(III) tends to readily react with other compounds in the solution and then precipitate out of the solution.
I use a single pass UV-C, so I see a minor loss of Fe chelation with 50/50 Fe-DTPA/Fe-EDDHA. I would switch to 100% Fe-EDDHA, but Fe-DTPA has some advantages. I’m hedging my bets using a mix of EDDHA and DTPA, even though I doubt I would see a significant loss of chelation if I used 100% Fe-DTPA with a single-pass UV-C. If I used RDCW or other recirc systems, I would go with 25/75 DTPA/EDDHA, or 100% EDDHA.
Recent research found UV-C didn’t affect tested macronutrients, including NO3, K, Ca, Mg, and SO4:
When using Fe-EDDHA, look for the product with the highest o-o %. I recommend Sprint 138 because it has the highest o,o at 5.2%. Much more on the topic of Fe-EDDHA in my thread here: