see my 2 year old post ==>>
https://garden.org/thread/view...
I start everything from seeds under lights. Started doing this in 1994 using plain old fluorescent shoplights 4100k with junk 0.85 power factor ballasts (1.00 power factor is considered to be 'normal' power output). The lights were on for 16-18 hours a day. Bulb wattage was 40 watts per bulb. I used 3 fixtures with 6 bulbs total per shelf. The light spectrum of the bulbs was far from optimal for growing plants. Inefficient, and too warm in the summer, but the seedlings grew OK.
Currently using commercial Phillips GreenPower fixtures (too expensive, but efficient low watts) and Phillips TLEDs 3000K. The TLEDs are being used in standard fluorescent fixtures that I have re-ballasted to 1.15 power factor. This in effect makes them HO (high output) LED fixtures.
The main reason for using the LEDs is to get the heat down on the plant shelves in the summer by reducing the overall wattage and the number of hours the lights are on. The LED lights are on for only 12 hours per day.
Ignoring the cost of the fixtures, the new Phillips T8 LED bulbs can be found on the internet for < $15 each. That still comes out to 6 x $15 = $90 per shelf. Still not cheap, but it works for me.
Bottom line is that even the old 1990's setup worked, but the basement working area is much more comfortable in the summer now (and the electric bill is much lower).
Commercial LED grow lights positive - compact fixtures, low wattage, low heat (approx 24 watts / fixture), using 3 per shelf.
Commercial grow lights negatives -
pinkish purple LED lighting is very hard on the eyes
cost is still way to high for the fixtures
TLED fixture positives-
uses existing fluorescent T8-bulb fixture
relatively cheap (mid cost)
TLED negatives-
fixtures more bulky
ballast + bulbs still generate more heat than the commercial fixtures
wattage better than fluorescent , but worse than commercial fixtures
