Lot's of questions, so I'll do my best to answer them all.
"What is degrees K?" - This refers to the color spectrum that the bulbs put out. The lower the degrees K, the redder the spectrum. The higher the K, the bluer the spectrum.
"How do I determine that?" - I'm assuming you're referring to determining the K readings on each bulb. The package you bought the bulbs in should have all relevant light readings, including degrees K, on it. If the bulbs are burning yellowish, they're around 2700K, clean white light is around 5000K, and slightly bluish light is around 6500K.
"How long should my lights be on?" - Depends on how many footcandles (a measurement of light intensity at a particular position/distance from the light source) your lamps are putting out. Most orchid growers I know use 10 or 12 hour days in the winter, and 14 hour days in the summer. I personally use 12 hour days all year round.
"How close to the plants should they be?" - This would depend on how many footcandles of light you get, and what distance from the bulbs you get those footcandle readings.
"i heard orchids need red spectrum which i'm sure is absent in the "daylight" bright white bulbs. " - Orchids need red light mostly for flowering, though they absorb all parts of the light spectrum, even some green. Most light gardeners I know use a mix of bulbs - 2700K and 6500K - to provide a full range of light to their orchids. The daylight bulbs still have output in the red light spectrum, just not as much output as the 2700K warm white bulbs.
And just to give you a comparison, here are the stats of my grow area and light setup, and what I grow using it:
- 27" deep by 49" wide by 3 foot tall.
- 2 GE Daylight 40watt T12 fluorescent tubes, 6500K, 3050 lumens per bulb.
- 2 GE Kitchen and Bath 40watt T12 fluorescent tubes, 3000K, 3400 lumens per bulb.
- 3 Bright Effects Daylight 26watt compact fluorescent bulbs (the screw-in type you're referring to), 6500K, 1600 lumens per bulb.
- 3 Bright Effects Soft White 26watt compact fluorescent bulbs, 2700K, 1750 lumens per bulb.
All of this comes to roughly 23,000 lumens in my grow area. My footcandle (FC for short) readings are, in distance from bulbs: 5" = 5000 FC, 10" = 3500 FC, 18" = 1500 FC. I grow standard sized Catts in this setup, their leaves all sit within the 3500-5000 FC range at all times. No scorching, no burning, nice green leaves with some purple edges. Lots of big blooms.
I urge you to find a light meter that will read footcandles in both sunlight and artificial light. I got mine at a local hydroponics store for $22. Once you have the meter, take some readings at different distances from your bulbs, and you'll know how far your plants have to be from them. And remember: because artificial light is constant, your orchids don't NEED to have the full recommended FC amount. I've bloomed mini-catts under just 2000 FC of light, and they've bloomed nicely, even though the recommended FC amount is 3000-3500.
Hope I've answered all of your questions, let me know if you have more.
-Tim C.
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