So glad my winter bulbs can enjoy the outdoors. However, I do have a small number of miniature geophyte aroids that grow and thrive under 1' x 2' inexpensive LED panels (10W each) (along with some cool tropical shade begonias and oxalis)...6" over soil surface, totally cool, so leaves can touch without damage. For brighter situations (something that needs to come in from the cool) I have some 1' x1' LED panel plant lights (20+W each) the exposed LEDs will burn leaves if they touch, part shade plants seem happy under those. Going to set up an LED spotlight on the Amorphophallus konjac bloom coming up, maybe it will end up shorter and more deeply colored. I/m also trying the winnow the collection of plants that need conditions beyond what I can provide inside or outside. Robert On Thu, Feb 24, 2022 at 4:46 PM oooOIOooo via pbs < pbs@lists.pacificbulbsociety.net> wrote: > There are many factors used to describe agricultural lighting. Technology > changes rapidly. Any Wiki page on lighting would be outdated in months. > > There are substantial lighting discussions in many plant groups on the > Internet. I think the best suggestion is to go to a hydroponics shop and > talk to them about lighting. > > Not many people recommend anything other than LEDs any longer. The > electricity efficiency is so much better than any other form of lighting > that there is no economic case for anything else. The lamps last longer; > the human eye doesn't notice it, but fluorescent tubes used for plant > lighting need to be replaced every 6-12 months. > > High-pressure sodium lights are dangerous. A person touching one will have > a third-degree burn before they notice the heat. They are extremely > inefficient, converting a large proportion of electricity to heat. > > Standard and T5 fluorescent tubes can be used. The T refers to the > diameter of the tube. T5s are narrower and hotter. Fluorescent lamps are > less energy efficient than LEDs. Their cost per hour lit soon exceeds LEDs > because the tubes need to be changed at least annually. Most growers no > longer recommend them. > > Plants can use photons that aren't in the narrow pink and blue chlorophyll > absorption peaks. You don't need to use those but you can. "White" LED > light is created by mixing LEDs emitting different wavelengths. There are > several LED combinations to get to white, not all of which are good for > plants. > > Color temperature measured in degrees Kelvin (K) refers to how the light > looks to a human eye. It is not related at all to whether the light > spectrum emitted is useful for plants. By random chance the combination of > phosphors used in old-fashioned fluorescent tubes to yield a 6500K color > temperature produced a spectrum good for growing plants. LEDs use different > technology so you can't use color temperature to select a good LED for > plants. LED manufacturers advertise a 6500K color temperature, but this > does not mean the lamp is good for plants. > > Agricultural lighting companies usually provide information on the photon > flux at different wavelengths. This can be used to calculate how efficient > the lights would be for growing plants in terms of useful photos per energy > input. LED manufacturers should provide the photon spectrum listing so you > can decide whether the lamp will be useful for plants. > > It gets very complicated, which is why I suggest getting a recommendation > from somebody who knows about these lights. I don't grow under lights so > I'm not that person. But I recognize a lot of the issues. > > Leo Martin > Phoenix Arizona USA > Zone 9? > > Sent with ProtonMail Secure Email. > _______________________________________________ > pbs mailing list > pbs@lists.pacificbulbsociety.net > http://lists.pacificbulbsociety.net/cgi-bin/… > Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> > _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>