I put together a few light shelves to do several things last fall. First I wanted to start Alpine strawberry seeds and fig cuttings for spring. Second I wanted to grow regular strawberries indoors for the winter. Most important to me was the cost of building and the electrical costs of running it. So the lamps were the starting point. Researching plant lights I found in a nutshell that you could buy specially made grow lights of many types......fluorescent, incandescent, mercury vapor, sodium and LED's. Pluses and minuses to each but the one that produces the most light at the lowest power draw and generates the least heat is the LED lamps. I tried the special red/blue grow light LED lamps and the common household LED lamps in identical settings and the same timers. I used the household lamps after looking at their light spectrum and finding that I could get the same red/blue light that plants require with the white illumination from the household lamps along with the yellow and green light that is not that important to plants. And I also found the the "special" lamps were not reliable, out of 12 only 7 are still working while only 1 in 28 LED lamps has failed. The growth was essentially the same over a 6 month period with the white LED and the red/blue lamps. The red/blue as you can imagine produces a strong purple light which is both annoying and makes all of you plants leaves look brown and dead! I found I was always moving them to a white light to see how they looked.
The white lamps I used are 40 watt equivalent lamps that only consume 9 watts of power each and I have bought for as little as $1 each at Lowes, usually about $3.50 for a pair. I purchased the lampholders at Lowes also for $1.50 each. The pictures show the lamps and lamp holders mounted on a homemade shelves and a three shelf plastic shelf also from Lowes. You can get 4 lampholders in about 1 square foot of shelf. So a 1 ft. by 3 ft. shelf will give you 12 lamps with 480 watts equivalent per light shelf. The actual power consumption will be 9 Watts X 12 lamps or 108 watts per shelf. So you get almost 500 watts of light equivalent for 100 watts of electricity. And the heat put out is only about 20% of the incandescent types. Light output in lumens for these bulbs is 800 each, so a 12 lamp shelf is getting almost 10,000 lumens. Bright....no.....BRIGHT!
I ended up with 40 lamps and holders, wire and a timer for about $125......plus shelves. See all the pics below, I also used reflectors to harness the light by reflecting it back inside the shelves. I used some silvered insulation plastic roll material from, as usual Lowes. No, I don't own stock but I do have a 5% discount!
How did it work? Very well, by setting the plant containers close to the light to get them started and move to a taller shelf as they grow and adjusting the lights by unscrewing some lamps if not used. I have found for me that rooting figs works best under the lights in a loose soil mix and well drained transparent cups. But outside in the sun is where they really take off as soon as the are ready for it. I also brought dormant potted figs inside in January to give them a 3 month head start that worked well for me.
So this is what I did. Is it right for you? If you are handy with tools and minor wiring or have someone that is then the answer is yes for starting plants indoors. Keep in mind this is an undertaking that requires daily care of the plants and a learning curve as to what works and what does not work so well for you. We will all have conditions that are different even indoors like temperature, A/C vents and humidity. I also added some styrofoam from shipping boxes to set the plants on as the slight heat from the lamps mounted under the shelf was great for the strawberry seedlings but dried out the fig cuttings too quickly. So called Fungus flies can be a real problem indoors. My solution was chemical warfare.....a very mild mix of pyrethrin and fungicide along with diluted fertilizer in the watering mix was the fix. Once the plants go outside they just get water. I am experimenting with small cuttings in the peat pellet starter pots indoors and they seem to like it so far.
If you decide to do this and have questions let me know, I am an expert at finding what doesn't work! Not too good at getting it all right the first time though. The wiring is the important but not difficult part......... IF you are handy with tools and have replaced a lamp socket or light switch you can probably do it. I can provide a pictorial or schematic if needed. Please keep in mind if you do not have the ability or have any doubts DO NOT ATTEMPT IT. Electricity kills!
Special red/blue and household lamps
Lamps and holders on plastic shelves
Wood shelves with reflector in back
Front "curtain" reflector and plants on the styrofoam