My grow light system
Thursday, April 14, 2011 
This simple set-up in my home office was inspired by Gayla's and Meighan's lighting systems that I read about earlier this year.
description
Shelves
I'm using two chrome 3-tier carts, similar to this Whitmor Supreme Cart with wheels & adjustable shelves. Each cart is about 24 inches wide, 13 inches deep and 33 inches high. Placed side by side (narrow ends abutted) the two carts' combined width is 48 inches, the same length as the fluorescent lights I'm using. Though I could have bought 24-inch fluorescent tubes to fit the width of one cart, the larger size is more economical -- only $2.00 more per light at the store where I purchased them.
Source & cost of carts: Homesense, $25 each, purchased 5 years ago to store office supplies.
Lights: SunBlaster T5HO fluorescent lamp & fixture sets
My system uses two T5HO 48-inch 54W 6400K lamps (lights). One light is between the top and middle shelves & one is between the middle & bottom shelves. In theory, I could stretch the system's capacity with two more lights: one suspended from the ceiling for plants on the top shelf & one suspended from the bottom shelf for young seedlings.
Source & cost of lights: West Coast Seeds, $31.99 each (February 2011 price). Though more expensive than standard fluorescent tubes, the lamp & fixture kit includes an electronic ballast so I eliminated the expense of a separate ballast.
Hanging hardware
Because the hardware that came with my SunBlaster lights is designed for mounting to wood or drywall -- not the open, wire shelves I'm using -- I devised a simple hanging system with large clips & hooks.
Bulldog-type clips, 1-inch capacity, 3-inch wide
Quantity needed: 4; two clips per fluorescent tube, one clip placed close to the ends of each light.
Source & cost: generic version of Boston® Bulldog® Clips from office supply store; about $3 for 2 clips.
The ballast, which is integral to the fixture, is just under 1 inch wide so the clips hold it snugly & securely. There hasn't been any slippage due to weight or breakage due to pressure since I applied the clips 4 weeks ago.
S-hooks
Quantity needed: 4; two hooks per light (or multiples of two if you want to link them together instead of using chain).
Source & cost: local hardware store; about $2 per package of 4 hooks.
One hook at each end of the light suspends the light from the shelf (see photographs above and below). The top loop of the "S" is placed over the middle wire of the shelf and the bottom loop of the "S" is threaded through the bulldog clip's opening. Hooks can be added (linked together) or subtracted as needed to adjust the height of the light above the seedlings.
As the seedlings grow, I'm also able to easily adjust spacing (by one-inch increments) between shelves. In the photo above, if you look closely at the front pole, you can see the top portion of the black plastic insert that holds the tier at the desired position.
I bought 4 feet of lightweight chain for under $3 which I haven't used yet. I prefer linking together S-hooks as it's quicker, simpler & less clunky. Chain would be useful if you were suspending lights from the ceiling or had large spaces between fixed shelves.
Other supplies:
Plastic trays with clear plastic domes for holding seedling pots. I purchased mine more than 15 years ago so I don't remember the cost or source. If I didn't have the trays, I would reuse the plastic containers from salad greens.
Reflectors would be a useful addition but I haven't yet found a local retail store where I can buy them.
evalution
Three weeks ago -- as soon as the first tomato seedlings germinated -- I turned on the switch on. An exciting moment! Today I have 29 young tomato, eggplant and pepper plants growing green, straight, strong and fast. Turning on the grow lights, brushing my fingers against the leaves, watering, rotating the pots and comparing growth rates have become a pleasant morning ritual.
Grow lights -- highly recommended. Much as I love window sills for many things, they mine aren't the best for nuturing young tomato seedlings.
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It's taken me a little longer than I planned to write this post so I'm going to publish it now & perhaps add some notes as I think of them.
I'm happy to answer your questions in the comments.