Squirel cage fans block the light, an important consideration if some plants need 12 hours of darkness to bloom. The axial fans Paul is talking about do not block the light; you would have to rig up something else to do that. The axial fans that are quiet, tend to have low cfm. Because small axial fan blades have so little surface area, they need to rotate fast in order to move a lot of air. (Paul) " Electrical and computer fans at low rpm are virtually silent,..." (Lermer) "Electrical" fans? I had thought all fans were electrical, although I suppose there might be little elves with hand-powered fans. "Computer" fans? I don't know what kind of fan Paul has, (perhaps the original WWII-era Eniac); but in all the computers I have seen, the axial fans in them are too small to be useful for plant room ventilation. (Dcarch) "The computer type of cooling fan is specifically designed for ventilating and cooling." (Lermer) Silly me, I had thought all fans were for the purpose of ventilation and cooling. Please, tell me where I could get some fans that are not. Ripley's Believe it or Not might be interested. (dcarch) "Squirrel cage (centrifugal) blowers are specifically used to overcome backpressure situations as in pushing air thru ductworks. It is never used for general cooling purposes." (Lermer) Squirrel cage fans have that capability, but they don't have to be used in ducting; in fact they are rated for different lengths of ducting starting with none at all. Normally I wouldn't use them without ducting (because of the higher cost) but they do block the light. If you read what I said, my first preference was for an open door with a 16" pedestal mount fan from Home Depot. Telling someone to make holes in their door and install axial fans in them, without warning them about light leaks (in and out) is irresponsible. (dcarch) "Before you use a 16" fan to blow on your seedlings, say goodbye to them first." (Lermer) I said, pedestal mount; which means, the height is adjustable. Jon didn't say anything about seedlings. Those can be placed away from strong air currents. The bigger plants would appreciate the air movement (as any but rookie growers know). (Object 16) "PHOTOSYNTHESIS IS OPTIMUM at 70-85 degrees." (Lermer) That's an incredibly ignorant statement. Where did you hear that? Generally, he optimum temperature is 76F. For every two degrees above that, you lose about 10% of the plant growth. This isn't apparent to the naked eye, except at extremely high levels. Above 76F you will see more green leaves because the leaf surface area increases (leaves become thinner) to transpire/cool more; and the leaves at such high temperatures tend to be more full of water. Once you weigh the dried mass, you will significant reductions in yield at 85F. Although light-on periods should have at least 70F. http://www.umass.edu/umext/floriculture/fact_sheets/greenh use_management/gh_cool_growing.htm "For many crops, media temperatures for germination should be between 72F and 76F. After a crop is established, most plants will tolerate non-optimal temperatures more easily. Seed germination is not the place to skimp on heat." (Lermer) Adult plants can usually tolerate slightly lower or higher temperatures, depending on species (where they evolved). A few degrees above optimum is a lot more harmful than a few degrees below optimum. (Object 16) "Plant growth is mainly a function of total number of photons - a rough measure of light intensity is lumens, so have a look at both lamps, and decide whether one or the other has sufficient lumens." (Lermer) "Lumens" is a "rough" measure, true; very rough, because it is biased toward the center of the spectrum. HPS reads very high in lumens because it is mostly yellow spectrum. However lacking a better common measurement, "lumens" is a factor to consider; but you should also consider spectrum. Generally you want a full spectrum, between 400-700nm, blue (about 420nm) and red (about 675nm) are the most important. For that, CRI (color rendering index) is a rough measure.

Love the indoor grow-light gardens, especially since we've already been down as low as -10C/14F, so if it wasn't for indoor gardening now, I wouldn't be doing any gardening at all. Those peppers were just planted 33 days ago?... wow, that's impressive. I started my indoor winter peppers in mid-July (Nagas) and mid-August (some unknown Thai-type), and the plants aren't much bigger than yours, though I do have lots of peppers set (very green, nowhere near ripe). I grew mixed-greens inside a few years ago (spinach, lettuce, etc) in a big tray... I did get several salads from it but didn't think it was worth repeating. I have never tried radish or celery indoors. Parsley does fantastic under fluorescent lights (I have 2 pots of it now)... basil is another grow-light success story you should try (I have Thai basil growing now, but every kind of basil I've tried under lights has done well).

DH is not in town right now but I'll have him install the new perimeter pendants in Sept. and then I can make a photo. This photo doesn't tell the whole story but you can see the ceiling fixtures and the fluorescents. Excuse the mess--I'm trying to move stuff around in the new space. Be patient here. Will try to explain. Our new kitchen is a 12 x 17 bumpout running the long way along the front of our house along our old 8 x 10 kitchen plus basement access, which have now morphed into a corridor and an eating nook and a closet; wrapped along the perpendicular end of the old kitchen/corridor and new kitchen is a new lobby. The Lobby and the old kitchen are really passageways--besides accessing the G-shaped kitchen through the gap in the G, the corridor-lobby has access doors to garage, front step, basement, dining room, kitchen closet, and coat closet. Not easy to understand this, but if you dig through my Flickr stuff you'll see the plan. Essentially, the halls make a T and the new kitchen cuddles into one side of the T and the dining room into the other side. So... We've put four matching 2-bulb Besa ceiling hugging fixtures along the T and two 3-bulb ones into the center of the kitchen. That means that we bought a total of 6 fixtures that all match, in order to try to homogenize the disparate parts. We'll also have matching white Quoizel pendants along the two parallel walls in the kitchen that run same direction as the stem of the T. (see a new post I made today). Are you using CFL's that were specifically designed for dimming? They ARE in the stores but I haven't tried them yet. Interesting that your kitchen code requires CFLs! I thought our community was restrictive but don't recall this requirement. The community does allow recessed cans in attics, but we chose not to do this because of energy and ice dam concerns. We are not allowed to put anything but fluorescents into closets. I have a young friend who has a 1950s kitchen that was always progressive and functional. She retained the ceiling fixture position when updating the space. She put in a large ceiling-mounted 1-foot hanging xenon? hallogen? something else? very bright mod light on her white ceiling which she feels is very sufficient for most kitchen activities. There is a light over the sink and another over the table and there is one in the range hood, but otherwise, I think that's it. She's 15 years behind me in the aging issues. Kitchen has a wall of windows. Please let us know how things progress in your project. Inquiring minds want to know. Here is a link that might be useful: note two ceiling lights and undercab fluorescents in partly finished kitchen

Looks like the setup modification was worth the effort. It's a much better distribution of light than before. Your tinfoil modification is creative and effective. =) I think Rina's onto something about letting some of your plants go dormant. After looking at your photo a while, I don't think it's possible to give them all enough light. Originally I wasn't going to have two light setups, but the light in my loft ended up being much darker than expected as fall came. =( My biggest succulent, a Euphorbia trigona, has been put on a very minimal watering schedule now with lower natural light... it's losing all it's nice leaves but I can live with it looking the same all winter (maybe that's even a good thing it doesn't grow much taller, ha). How many 1'x4' shelves would you need for all your plants if you cram them all in together? Maybe you can prioritize half your collection or more (with one layer of light). Or if you're able to put in a third shelf or skinny table, then you could get a bit better utilization of your lights. The reflectors look to cover have an area that's much wider than 1', although the walls help by giving you a bit of bounce. Putting your shelves back to back would give better use of space on the top level, but the bottom levels become harder to access and probably would get barely any light at all. If anything, try to visualize how the light is distributed from each of your lamps. Two would be very distinct circles and the other a sort of oblong shape. Then place your highest light plants in the brightest spots and ones with lesser needs (or you care less about) around the edges. I'm still shuffling my pots around every few weeks... I think the more you look at it the easier it gets.