First you want your lights to move, not the shelves. Putting chains on the lights make them easy to move up and down.

Second you want your shelves to be wide enough to handle two fixtures. Forget the grow lights, go for the cheap, brightest lumens you can get. Believe it or not, you can bloom orchids under the white cool bulbs - you don't even need the "warm" fluorescent to make things bloom.

I pinch back every type of seedling I grow except daylily and hosta seedlings. After a tomato has 5 or 6 leaves, pinch them back to 4 leaves and you will get branching and a shorter more compact plant. I pinch all annuals and perennials back to get the compact plants.

Your shelves should be wide enough to handle a seed tray running front to back instead of side to side. You can then get four trays per shelf instead of the two that fit under the fixture (more plants to grow).

Forget the expensive mylar and go for a flat white surface to help reflect the light. It is just as effective and much cheaper. I use the insulation styrofoam type board (about 1/2" thick) from one of the big box stores. It is cheap and easy to fit around your shelves.

I already have daylilies and hosta seedlings going and am getting ready to start my annuals. By the time I can put them out in May, they are blooming and bigger than the ones I can buy.

Brooke

Almost forgot - if you have trays where the heights are very different, I put trays on boards to raise that particular tray higher and still accomodate even taller plants.

Yardenman,

Home Depot's Commercial Electric model 732-334 shoplights hold two 4-foot T8 or T12 fluorescent bulbs and they are only 5 inches wide, so you can mount three of them over an 18-inch shelf or four of them over a 22-inch or 24-inch shelf. Incidentally, they cost only about $8 each and Philips cool white T8 bulbs are $19.95 for a box of 10 at HD, which makes them only $2 each.

Those Home Depot shoplights are readily converted to an overdriven mode, which puts out 50% more light than the standard configuration. You can learn how to overdrive your fluorescents in the I have found the BEST cheap fluorescent ballast/fixture message thread.

Three overdriven HD shop lights put out the light equivalent of nine fluorescent tubes. Four overdriven shop lights put out the light equivalent of twelve fluorescent tubes. That's a lot more light than you have been giving your tomato seedlings. That should keep your tomatoes from becoming leggy.

I also provide a breeze for my seedlings with small fans, and that "exercise" makes them very stocky.

MM

Your old fluorescent fixtures are garbage, I suggest you throw them away and get new ones. I can't be 100% sure of course, but a few hints in your message suggest you have essentially obsolete technology. Get theeself some decent modern fluorescents and you'll probably have about 50% more light before you even start, they'll probably also be slimmer and you can perhaps fit in extra tubes depending how wide your shelves are.

Make sure you have good reflectors above the tubes, the reflectors on cheap shop lights are not particularly good. Also add reflectors or baffles at the sides when you are growing tall plants, you might as well keep all that light on the plants. Remember that shoplights are designed to evenly light a wide area of a room, not at all what you want. The only exception would be where you have a decent amount of natural light, don't block it.

If you can get a decent amount of natural light on your plants, then that's great, but be careful about having direct sunlight on very small seedlings when they are still under plastic, they will rapidly overheat. Try to actually measure how much natural light you have, the human eye is useless at judging it. Direct sunlight will always be brighter than any fluorescent light you provide, but what you might think of as bright indirect light from a south facing window may be ten or a hundred times too little for the plants.

Starting outdoors in a mini-greenhouse or cold frame you will have no problems with etiolated floppy plants. The cooler temperatures and light that is probably brighter than anything you will provide indoors even in February mean nice compact plants. But they may start a little slower than ones indoors in the warm. If you can grow your plants where the night temperatures drops around 20F, much more than most people can manage indoors, then that will make a huge difference.

Yardenman,

You might want to take a look at the Inexpensive Seed Starting System message thread.

MM

Thanks for all the help, everyone! Some of the ideas, I had thought of but didn't know if they were good ideas, some were new. And I still am unsure about the lights to use (full spectrum just "ought" to be better, but maybe the difference over the cheap tubes is very slight).

The Chrome Industrial Shelving sounds like quite a bargain and I may get that, but I also like to build things of wood, so I may basically copy it. The light fixtures I have have side reflectors to direct light downwards, so I think that will those will be OK. I plan to put a back on the shelf structure, and am thinking covering it with aluminum foil (should be a good reflector).

I'm going to attach 2 2-bulb fixtures under each fixed shelf. I will make the shelves fixed (trying to move the shelves up and down never really worked). As it turned out, I've found it easier to place spacer boards under the trays rather than move the shelves (as someone mentioned doing). Pieces of 1"x1"s, and 2"x2"s work great and ½" plywood cut to the size of the trays provides stability.

Maineman  Thank you for the idea of overdriving the lights. It makes me a bit nervous to do that, though, and I am not good with electrical changes. I will try just doubling the regular lights this year. Also, I have 2 small oscillating fans to encourage stem strength. Admittedly, I usually forget to use them, but I think it is a real benefit to the seedlings. I would like to set them up on stands with timers to give the seedlings 15 minutes of breeze every 2 hours. The breeze is good for strengthening the stems, but I don't want to dry out the soil either. I will make sure to use them this year!

Shrubs and Bulbs  I suppose I will have to set up a cold frame and monitor the temperature. I know that cars warm up with all the sunlight passing through the glass, but I can just never quite get myself to trust my tender seedlings to a coldframe. I really need to prove to myself that it works! No harm in building one and trying out a few sacrificial seedlings. I have plenty of seeds. And I even have a glass storm door I have been saving for with the idea of using it as a cold frame cover. ï

I start most of my annuals inside under florescent light fixtures in my unheated basement where the temperatures under the lights stay around 60 - 70 degrees. Since I am growing many different types of seedlings in a small space & it is important to keep the seedlings within inches of the light, I use a system similar to putting boards underneath the plants. Except I substitute sheets of styrofoam (like found inside of commercial boxes used to ship items) to customize the closeness of the different seedlings to the same light fixture. Several advantages of the styrofoam are: 1) it is white & reflects light backup around the plants 2) it is easily cut/broken into sizes that are easy to use 3) comes in lots of thicknesses 4) its' free.

I did some research about reflecting light, and actually white is better than mirrors or aluminum. I bought something called "visqueen" (can't remember how to spell it) - it's a thick plastic film that is white on one side and black on the other and tacked it to the wall behind my lights. Works well and protects the wall from splashes too.

I too prefer to prop plants rather than move lights. Thanks for the styrofoam idea!

actually white is better than mirrors or aluminum

Actually that's not true. Aluminium has a reflectivity around 90%. Aluminium reflectors are the most robust and efficient solution but they are also quite expensive and must be kept clean and free from corrosion (salt from sea air or repeated condensation causes a white bloom which reduces the reflectivity). Aluminium foil, cooking grade, is too thin and lets around half the light straight through so don't use that. Mylar has a reflectivity around 95% but can be difficult to use, easy to damage, and it is flammable! Normal back-surface mirrors have a reflectivity around 90% but are not good for plant reflectors because the light is reflected "like a mirror", it will either miss your plants or hit them in a focussed way which will be damaging. White paint has a reflectivity up to about 90% but usually more like 80%. Some are lower, choose something like a latex roofing paint, or just use indoor flat matt paint, you can always repaint frequently. Avoid oil-based "gloss" paints, reflectivity is significantly lower and they fade very quickly under intense light. Visqueen has a reflectivity of 85%, some of the hanging and durability problems of mylar, I haven't had the opportunity to try burning it, I imagine it would certainly melt and possibly burn with a noxious smoke.

I use flat white paint on all surfaces around my plants, it is nearly as effective as other solutions and better than some, cheaper, and much more convenient. An aluminium reflector just above fluorescent tubes or HID bulbs is helpful because the extra few percent efficiency makes a difference with the really intense light there.

shrubs, thanks for the clarification. I was referring to aluminum foil, not aluminum reflectors, but that's not what I typed!

There are heavier grades of "extra-thick" cooking foil available now. I need to run some tests and see how much light they reflect.

I'm still interested in whether the visqueen burns, hint, hint.

Barium sulfate can be mixed with flat white paint to increase it's reflectivity. Just don't mix too much barium sulfate as it doesn't adhere very well to surfaces when used in higher concentrations with paint (>50%)

Here is a link that might be useful: A mixture of barium sulfate and white paint is a Low-Cost substitute reflectance standard for Spectralon

I would guess the visqueen would at least melt and stink like heck. I'm pyrophobic so I won't be running any tests myself, sorry, shrubs! ;)