The Orchid Garden

Ultraviolet light/viruses/hydroponics

Question:

Wendy, Frankly, I haven’t seen the ads you are referring to.  However, ozone works quite well for removing odors.  So, they do a lot of the things that are claimed.  However, they can also do other things that we don’t want to happen…..

Just a little note:  George Herriman, the creator of -Krazy Kat-  had an earlier cartoon strip called –Major Ozone’s Fresh Air Crusade–.  At one time ozone was considered to be healthful.   The Air Force experimented with liquid ozone as a means of "spiking" rocket fuels back in the 1950-s and early ’60’s.  They gave it up after discovering that ozone was too unstable for safe handling in bulk. It had a tendency to explode spontaneously when jostled.   BTW, the city of Philippi, WV  (I live there)  uses UV at its sewage treatment plant.   The microbiology class at the local college set up a project to monitor the microbials in the discharge water.  They couldn’t get much of anything to grow.  The UV killed just about everything. J. Del Col

Response:

Shucks!  And I have two orchids hanging in the skylight over our bed and was hoping they would benefit from all that snoring-generated co2!! — Reka http://www.rolbox.it/hukari/index.html "I hate flowers – I paint them because they’re cheaper than models and they don’t move."        –Georgia O’Keeffe | | I probably wouldn’t worry too much about the timing except to say that c3 | and c4 plants fix during the daytime and cam plants fix at night…. and | that the majority of your orchids would not be cam (but some are e.g. | rhycostylis gigantea) so better off releaseing co2 during daytime

Response:

Thanks again, John — a good article. I really have doubts about these things and there seem to be no controlled studies to back up the stupendous claims. I have eliminated ozone and ion generators from consideration for my greenhouse, but I am still thinking about carbon dioxide generation, since there actually are studies about that that show it is beneficial to plant growth, and that carbon dioxide is quickly depleted in a relatively tight greenhouse. The problem with orchids is that some are C3 and others C4 plants, and fix carbon dioxide at different times, some during the day and others at night. But perhaps some generation at fixed times during the day or night would help. Or maybe just for seedlings.

Response:

mmmm…. a few years ago at an Asia pacific orchid conference there was a guy from Japan (?) who had done a lot of work showing that oncidiums flower much much much nicer (more branches, larger flowers, more flowers, longer stems….) when given additional carbon dioxide (suggestion was if you had an enclosed glasshouse that you set up a beer brewing vat/container which would produce elevated co2 levels…. note this would also affect ethylene levels) I probably wouldn’t worry too much about the timing except to say that c3 and c4 plants fix during the daytime and cam plants fix at night…. and that the majority of your orchids would not be cam (but some are e.g. rhycostylis gigantea) so better off releaseing co2 during daytime more in mornings/afternoons than in the peak times when light levels are toooo intense for the plant to risk doing too much photosynthesis (but again am really over simplifying it…). An interesting point to note is that the most limiting factor in plant growth most of the time is carbon dioxide levels (not nutrients and not light although these do help push growths along…) cheers (happy beer brewing….) Thanks again, John — a good article. I really have doubts about these things and there seem to be no controlled studies to back up the stupendous claims. I have eliminated ozone and ion generators from consideration for my greenhouse, but I am still thinking about carbon dioxide generation, since there actually are studies about that that show it is beneficial to plant growth, and that carbon dioxide is quickly depleted in a relatively tight greenhouse. The problem with orchids is that some are C3 and others C4 plants, and fix carbon dioxide at different times, some during the day and others at night. But perhaps some generation at fixed times during the day or night would help. Or maybe just for seedlings.

– Leanne Forsyth Room 532 Hines Building Phone 3365 2854 School of Life Sciences University of Queensland, Brisbane Australia

Response:

Wendy, The biggest problem I’ve seen with the negative ion generator is that most of the units do not have a ‘collector’ to pick up the charged particles. The dust in the air picks up the charge and then will head for the walls, tables, drapes, etc. and collect there.  I’ve heard of people having to do a lot of cleaning after using the generator. Of a personal note, I found that, when I had to spend much time in a room with a negative ion generator, that I ended up with a sore/scratchy throat. Haven’t seen anything written about that, but it did affect me. One site I found against ion generators is: http://www.netasia.net/users/truehealth/Negative%20Ion%20Therapy.htm .  You can decide for yourself. John G. Talpa, CWS-VI Certified Water Specialist JT Company

– Hide quoted text — Show quoted text – Thanks, John, that helps quite a bit. I am in the process of building a greenhouse and had read about the wonderful benefits of ozone generators (you can see such claims by doing a google search with those words, or visit a site such as wormsway.com, or other general indoor gardening site — hydroponics stores in particular have them, perhaps for the odor-reducing qualities you mention) when I came across a federal study that basically disavowed all of the supposed benefits of ozone. The claims are incredible — cleans the air so you can sleep better, doubles plant growth, etc., with no mention of ozone’s polluting nature. But now that I have your attention let me ask one more question. What about the "negative ionization" generators often sold on the same page? Do they do anything helpful or harmful? I asked a chemistry prof and she told me that the negative ionization produced after an electrical storm is dissipated quickly and she did not believe these generators could produce anything useful that would last. Thanks.

Response:

Thanks, John, that helps quite a bit. I am in the process of building a greenhouse and had read about the wonderful benefits of ozone generators (you can see such claims by doing a google search with those words, or visit a site such as wormsway.com, or other general indoor gardening site — hydroponics stores in particular have them, perhaps for the odor-reducing qualities you mention) when I came across a federal study that basically disavowed all of the supposed benefits of ozone. The claims are incredible — cleans the air so you can sleep better, doubles plant growth, etc., with no mention of ozone’s polluting nature. But now that I have your attention let me ask one more question. What about the "negative ionization" generators often sold on the same page? Do they do anything helpful or harmful? I asked a chemistry prof and she told me that the negative ionization produced after an electrical storm is dissipated quickly and she did not believe these generators could produce anything useful that would last. Thanks.

Response:

John, I know ozone is a serious pollutant. Why do so many horticultural sites sell "ozone generators" as if they are air cleaner?

Response:

Wendy, Frankly, I haven’t seen the ads you are referring to.  However, ozone works quite well for removing odors.  So, they do a lot of the things that are claimed.  However, they can also do other things that we don’t want to happen. Many hotels will place an ozone generator into a room where there has been smokers or other things have gone on that cause a room to be unuseable.  In a short matter of time, the offending odors are gone.  During the time that the ozone generator is operating, no one is allowed in the room.  The room cannot be occupied until the ozone has dissipated to an acceptable level. This is because ozone causes damage to mucus membranes, lungs, etc. I had one call about water treatment a while back where the woman had some health problems and was concerned about her drinking water.  In talking with her, I found out that she had an ozone generator in her house that was on at all times and then she bought one for her car for when she traveled.  I told her to research ozone a little further and to get the technical data from the manufacturer proving that the units met the standards.  I wish she had gotten back to me after discontinuing the ozone to know if she improved. A number of ozone units on the market had to be removed until they met the federal standards for ozone levels because they produced too much.  But, that has not prevented the sales of such units.  Quite often, a scientific report will come out showing the beneficial effects of a given technology. Some people will then run with that information and use it to sell what ever product they create before knowing anything more about the technology. My personal belief is that many of the problems are caused by people who get over enthusiastic about what they are selling and don’t really know their product.  They can get so caught up in the ’sale’ that they will say whatever is necessary to sell.  I find it all the time in water treatment. As a dealer, I investigate the products I find interesting before I decide to sell them.  Most of the time, I won’t even think about carrying a product if the company has been in business less than a year because many companies don’t last a year, but I still have to answer to my customers if I sold them the product. As consumers, we need to look deeper into what we are purchasing to know if it is right for us, require proof that it does what they say it will do, and find out if there are side effects from the product.  Sometimes, even that won’t be enough. Well, I’m off the soap box.  Hope this helps. John G. Talpa, CWS-VI Certified Water Specialist JT Company

– Hide quoted text — Show quoted text – John, I know ozone is a serious pollutant. Why do so many horticultural sites sell "ozone generators" as if they are air cleaner?

Response:

Ray, Just so you know, the pricing on UV units has steadily dropped. For example, now, going from 3/4 gpm to 2 gpm is about $20.  Then, going up to 5 gpm is another $40.  Of course, units are available for any water flow you want. While this might be more than some want to spend, it is much less expensive than just a few years back.  When considering using hydroponics for growing orchids, it would be money very well spent.  You would be able to treat all of the water rather than a side stream. If sized properly, UV can attain very high ‘kill’ rates.  99.99% kill has been the normal standard for UV units.  Now, the units are rated at mj/cm2 dosage rather than kill rates.  So, it is just a matter of using a Dose-Flow chart to determine the proper sizing for the dosage required. John G. Talpa, CWS-VI Certified Water Specialist JT Company – Hide quoted text — Show quoted text – Al, Most of us shy away from "community water" sources for fear of spreading disease.  While I have not used UV on plant water supplies, I have on marine aquaria. They ain’t 100% effective, and you have to replace the bulbs periodically to maintain the intensity. One of the problems is that you need a fairly long exposure time to really get a high kill rate, meaning that you can only pass a portion of the water through the unit, and that is at a slow flow rate.  With a larger UV unit, that’s not an issue, but the $$$$ might be. — Ray Barkalow < First Rays Orchids http://www.firstrays.com Secure Online Ordering & Lots of Free Info! Hello, is there anybody out there who uses ultraviolet light in the water circulation systems of their hydroponics setup to destroy pathogens who can tell me if it also helps keep down the transmission of viruses from plant to plant via the circulation system?  How often do you have the plants in the system tested for virus?

Response:

Hello, is there anybody out there who uses ultraviolet light in the water circulation systems of their hydroponics setup to destroy pathogens who can tell me if it also helps keep down the transmission of viruses from plant to plant via the circulation system?  How often do you have the plants in the system tested for virus?

Response:

Al, Most of us shy away from "community water" sources for fear of spreading disease.  While I have not used UV on plant water supplies, I have on marine aquaria. They ain’t 100% effective, and you have to replace the bulbs periodically to maintain the intensity. One of the problems is that you need a fairly long exposure time to really get a high kill rate, meaning that you can only pass a portion of the water through the unit, and that is at a slow flow rate.  With a larger UV unit, that’s not an issue, but the $$$$ might be. — Ray Barkalow < First Rays Orchids http://www.firstrays.com Secure Online Ordering & Lots of Free Info!

– Hide quoted text — Show quoted text – Hello, is there anybody out there who uses ultraviolet light in the water circulation systems of their hydroponics setup to destroy pathogens who can tell me if it also helps keep down the transmission of viruses from plant to plant via the circulation system?  How often do you have the plants in the system tested for virus?

Response:

another down side of using UV lights is that when you leave them on for a long time they can cause a build up of ozone (not to sure if they are catalysing the reaction  and creating it or just attracting it) which can be harmful for humans (and dogs and cats too….) cheers – Hide quoted text — Show quoted text – Al, Most of us shy away from "community water" sources for fear of spreading disease.  While I have not used UV on plant water supplies, I have on marine aquaria. They ain’t 100% effective, and you have to replace the bulbs periodically to maintain the intensity. One of the problems is that you need a fairly long exposure time to really get a high kill rate, meaning that you can only pass a portion of the water through the unit, and that is at a slow flow rate.  With a larger UV unit, that’s not an issue, but the $$$$ might be. — Ray Barkalow < First Rays Orchids http://www.firstrays.com Secure Online Ordering & Lots of Free Info! Hello, is there anybody out there who uses ultraviolet light in the water circulation systems of their hydroponics setup to destroy pathogens who can tell me if it also helps keep down the transmission of viruses from plant to plant via the circulation system?  How often do you have the plants in the system tested for virus?

– Leanne Forsyth Room 532 Hines Building Phone 3365 2854 School of Life Sciences University of Queensland, Brisbane Australia

Response:

Leanne, Ozone buildup is a common occurrence in UV systems used in air ducts, air purifiers, etc.  In fact, that is one of the reasons that I don’t sell the type of units that are commonly found on the open market.  Even the electrostatic air cleaners that are found in central heating and cooling units are known for ozone production. However, in the UV units used for water disinfection, I have not found any literature citing ozone production as a problem.  Ozone has a distinctive odor and I have not noticed it around any of the units I have installed. Plus, none of my customers have complained about any ‘odd’ odor from their units.  This is probably due to the fact that there is very little contact with air in a water unit.  The UV goes from the bulb, through a small air gap that is basically a dead air space, through a quartz tube, into the water. Actual ozone producing systems use UV technology to produce the ozone if a minimal amount is needed and, when larger amounts of ozone are necessary, corona discharge (similar to lightning) is used to form the ozone. Now the opposite side.  UV units, using a different portion of the UV spectrum, are used as an ozone distruct system to destroy excess ozone that outgasses from an operating ozone system. This is probably more than you wanted to know, but I hope it helps. John G. Talpa, CWS-VI Certified Water Specialist JT Company

– Hide quoted text — Show quoted text – another down side of using UV lights is that when you leave them on for a long time they can cause a build up of ozone (not to sure if they are catalysing the reaction  and creating it or just attracting it) which can be harmful for humans (and dogs and cats too….) cheers Al, Most of us shy away from "community water" sources for fear of spreading disease.  While I have not used UV on plant water supplies, I have on marine aquaria. They ain’t 100% effective, and you have to replace the bulbs periodically to maintain the intensity. One of the problems is that you need a fairly long exposure time to really get a high kill rate, meaning that you can only pass a portion of the water through the unit, and that is at a slow flow rate.  With a larger UV unit, that’s not an issue, but the $$$$ might be. — Ray Barkalow < First Rays Orchids http://www.firstrays.com Secure Online Ordering & Lots of Free Info! Hello, is there anybody out there who uses ultraviolet light in the water circulation systems of their hydroponics setup to destroy pathogens who can tell me if it also helps keep down the transmission of viruses from plant to plant via the circulation system?  How often do you have the plants in the system tested for virus? — Leanne Forsyth Room 532 Hines Building Phone 3365 2854 School of Life Sciences University of Queensland, Brisbane Australia

Response:

Filed under: Growing Orchids

Related Posts