I have a large three tiered set up on wheels, and a smaller one that sits on a table. They cost more than makes sense if you are growing plants to save money, but I've been using them for more than ten years and love the convenience. The trays hold water, the light fixtures have outlets i use for heat pads and timers. Each tier has its own outlet. The only down side, besides the cost, is that each of the shelves are made up of two four foot trays, and plants grow at different rates, but it's hard to adjust the lights for plants of different heights. I put the seedling trays on things to raise them. I consider it a good value for someone with more money than time. It is reliable, and wattage has not been an issue. I only use it for about two months a year, in my garage in N California. I probably missed a question or too. Sorry. My son is studying engineering too! He helped me with a solar powered water fixture.

There was an earlier post that if you provide enough of each necessary wavelength that you will succeed. I agree after researching this same topic. The "NASA" mix of 60 blue and 165 red LEDs (225) total is for the monoculture studies they were conducting. Reviewing the short section of Rebecca Northern's Home Orchid Growing brought my answer into focus: Growers have been trying to optimize light sources since windows have been invented. The short and simple answer is that plants need enough of the right photons with energy to power the chlorophylls for sugar production. The power generated has to exceed the power expending in growth and maintenance activities so day and night time temperature become relevant. The light mixture and amounts differ among plants because light sources at the earth differ by altitude (bluer at high altitudes and redder at lower altitudes) and the position of the plants in the forest canopy (higher intensities higher up in the canopy and lower intensity on the forest floor). Orchids are in particular aren't on the top of the plant food chain - they succeed as opportunists hence the variety of species with specific niches and gimmicks to manipulate pollenation and seed spread. With respect to light, one will probably find different ratios of chlorophyll a and b among the different orchid varieties. Botanists find this true among the variety of plants that have different cell wall thicknesses to exploit higher or lower light intensities ( photosynthetic photon flux density), i.e. the overhead light flickers on leaves. Also the reflected and filtered light through forest canopies changes the light spectra falling on leaf light receptors. It becomes greener and yellower. Plus light spectra change with time of day and season. Plant growth cycles change the mix of reflected and reflected light. For growers using artificial light, light intensities drop off with the relation of 1/r**2. This is why high intensity lamps on the 20 ft high ceilings of factories can be rationalized in place of fluorescent lamps over the work tables. There is a higher operating cost that is offset by light availability over a wider area plus the less tangible issues of convenience and work efficiency. For large and tall plants, the fall off of LED intensities require additional light at the sides if leaf surfaces aren't lighted by top lighting. I think the best articles on light to date come from marijuana growers. Light intensity and lumenosity changes with the plant growth cycles. Seedlings would intuitively have thinnner cell walls and only need low light intensity. As plants mature and cell walls change to support a larger plant, light intensity requirements change. The amount of plant mass increases so the amount of light must meet this demand. At flowering time the plant growth slows down. For some orchid varieties, this would coincide with shorter light exposures per day / night cycles. Light frequencies might also change, e.g. red vs. blue I considered high intensity LEDs but currently is a tradeoff between brightness and junction temperature. Higher power generates more heat that must be removed to receive full benefit. As the LED junction temperature increases, light output falls. High temperatures and over driving electric current through LED shortens operating life from the 100,000 hour life commonly cited by LED manufacturers. Some Phillips Luxeon LEDs are dropping in price but the output light frequency might not be the best match with chlorophyll energy absorption frequencies. One do-it-yourself LED kit vendors announced a Cree LED kit. Maybe this match may be better. For now, I am going to try the high brightness 5 mm blue LED panels and try minimizing the LED-to-leaf distance without overly distorting the plant growth. Beside, from my thermodynamic lessons, the most efficient overall process energies are the ones that occur closest to ambient temperatures. That is why fluorescent tubes are less expensive to operate than incandescent bulbs if you can get enough light from them for your particular plants.

Thanks for all the tips, sorry it's been some time since I checked this thread. I've unfortunately been battling spider mites :O... definitely learned my lesson about ordering plants... don't do it! Glad you noticed the black tips on the roots. I actually found out what was going on there.... I have an acrylic divider between my 2 plants that sometimes gets knocked a bit, and I used to rotate the plants around and fiddle with em too much. So I think some slime or whatever was getting on the roots from the acrylic divider and too much touching the plants. It was only the roots right by that divider that got those tips. But its funny you mention H2O2 since I actually tried that before I realized what was going on... and the roots looked like ASS. I used arond 2ml/gal. I waited 3 full days after the peroxide, and there was ZERO root growth, and a LOT more dark coloring on the roots. Then I switched back to Bennies, cut off tons of roots... and the roots started growing again. Very interesting you suggest a ph near 7. That's alot higher than everything I've read. Most sources say 5.8-6.0, but I've also seen a few that say 6-6.5. You're the first person to suggest 7.0 so I'm very curious how you came to that conclusion. I think you raise a VERY good point about knowing when to trash plants. I will be moving into a new house next month, and starting a much larger grow, so I will most likely be trashing these plants unless I can be confident the mites are dead. Currently I have taped up my cabinet with a no-pest-strip inside. I tried neem spray; I think I overdid it since it totally fried one of the plants. I now know that it would have been a good idea to spray just pure water afterwards to get rid of excess residue. I'll post some pics next.

These are three DIY LED spotlights with different lens and reflector systems: http://www.general-cathexis.com/images/LedSpotLights.jpg Left to right: 1. Eight "3W" 660nm LEDs with 20mm reflectors. http://www.general-cathexis.com/images/LED20mmReflectorAndLens.jpg Spot projected 100 inches on ceiling with tiles 4.375 inches apart: http://www.general-cathexis.com/images/LED20mmReflectorAndLensSpot.jpg I calculate the beam angle to be approximately degrees 2. "10W" "full spectrum" LED with 90mm reflector a. without lens; http://www.general-cathexis.com/images/LED90mmReflector.jpg Spot projected 100 inches on ceiling with tiles 4.375 inches apart: http://www.general-cathexis.com/images/LED90mmReflectorSpot.jpg I calculate the beam angle to be approximately 35 degrees b. with Fresnel lens: http://www.general-cathexis.com/images/LED90mmReflectorAndLens.jpg Spot projected 100 inches on ceiling with tiles 4.375 inches apart: http://www.general-cathexis.com/images/LED90mmReflectorAndLensSpot.jpg This is the most uniform of the spots. I calculate the beam angle to be approximately 15 degrees. 3. "10W" "full spectrum" LED with 44mm reflector and lens: http://www.general-cathexis.com/images/LED44mmReflectorAndLens.jpg Spot projected 100 inches on ceiling with tiles 4.375 inches apart: http://www.general-cathexis.com/images/LED44mmReflectorAndLensSpot.jpg I calculate the beam angle to be approximately 27 degrees.