Time has finally come to upgrade the light table for seed starting. The old unit made out of a shop light and wood scraps way back in 2003 has reached its sell-by date. I needed something a bit larger and versatile. My first thought was to go full LED and build my own units. Full spectrum high intensity LED chips are cheap. The real work comes in building the power supplies, cooling fans and figuring out the circuitry and mounts. Commercial units are becoming available (mainly to supply the cannabis trade), but they are not quite there yet. Some are rather pathetic, not even high output but consisting of arrays of circuit board type LEDs.
The seed catalogs offer multi-shelf fluorescent units that are way too pricey and under powered. They do look good but I decided to compromise by building my own fluorescent tower unit. I began with a 5-tier steel NSF-grade shelving unit from Lowes. Because I wanted to be able to move this thing around the house easily I sprung for the caster wheels too. They work like a dream.
The rest of the components are right off of Amazon. The lowest shelf contains the seed flat heating pad resting on top of a piece of pink commercial grade wall foam board. This is where the flats will sit under a humidity dome until the seeds sprout. After which they will be moved up to one of the light shelves. One shelf contains a smaller FLT22 Agrobrite unit from HydroFarm while the other contains a larger FLT44 unit. The remaining top two shelves will be for storage and future expansion.
Agrobrite units are rock sturdy and well priced. They really can't be compared to shop light units. Using the newer T5 tubes, they are high output and full-spectrum designed specifically for plant growth. They come with a loop hanger on each end. Making use of those I added on Niteize CamJams to make height adjustment easy. I even kept the para cord the jams came with. They work beautifully and are plenty strong enough to support the weight of the largest light unit. All I did was cut the cord in half so that each jam had an equal sized piece. A loop and hog-nose clamp secured the cord to the light loop. I put double knots in the other end to limit slippage through the jam mechanism. Some caution is needed when initially setting these up to make sure the correct end is weighted and adjusting so as not to drop the units.
For power, I chose the Apollo 24-hour programmable surge protector power strip. It contains a row of outlets controlled by the timer and an uncontrolled row for "always on" (used here to power the heating pad). It was securely attached to the end of a shelf by drilling (very carefully) through the surface mounting holes in the back of the unit through the front housing. Be very careful here not to breach any of the internal wiring or interfere with the face of the timer dial.
Final attachment was via a pair of wide washers and two #10-32 2 in machine screws, locking washers and nuts. Not wanting to cut down the power cords the excess length was bundled and zip-tied to the frame and out of the way.
Light Specifications:
Agrobrite FLT22: containing two, 2 ft, T5 wide spectrum high output fluorescent tubes. Total lumens: 4000 at 6400K
Agrobrite FLT44: containing four, 4 ft, T5 wide spectrum high output fluorescent tubes. Total lumens 20,000 at 6400K
Not counting upgrades to the drip tray and new sets of 1020 flats, etc. I was able to put this together for about $300.
The Greenhouse Megastore is top notch for seed starting materials.
