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Making sense of lighting terminology?
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Posted by jane_d 5a (My Page) on Sat, Jan 19, 08 at 10:33
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OK. Excited new gardener here. The bed was tilled in the fall and compost left to seep in. Santa brought me seeds for tomatoes, pumpkin, cucumber, lettuce. Now the potting mix is mixed and the fertilizer is at the ready. I have trays set to lay on top of my approx 3'x4' boiler tank in the laundry room, where the surface stays around 50-70 degrees. (Space is an issue; I have no spot above 40 degrees in which to put shelves.) I don't have any good indoor light, but I do have scrap lumber and chains from which to hang grow lights. I thought I'd just go out this weekend or next and pick up some fluorescent lights, maybe some reflectors with them.
Then I thought I'd check this site for background info first. Thousands of K's? T8, T10, T12? TCP? MH? LPS? HPS? CRI? People are talking about spending hundreds of dollars???
Suddenly I feel like I'm getting my first mortgage again.
What do all these letters and numbers mean, and how important are they if I'm not growing prize roses? (If I get competitive at all, it will be with pumpkin size...) If I run out to the local hardware store and get some $10 shop lights, will I be planting my own healthy seedlings come spring or running out to the nursery to spend more money on someone else's? I feel like I could research this until it’s too late to get started...
Thanks very much in advance for any help!
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Follow-Up Postings:
RE: Making sense of lighting terminology?
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| Just go buy some cheap shop lights at the local home store. T8 is better than T12, electronic ballast is better than magnetic. Get 2 cool white tubes, or a mix of 1 cool white and 1 warm white tube, per fixture. Keep the fixtures within 1 to 2" of the top of the seedlings at all times. There! Quick and dirty info, you're good to go! Have fun! It doesn't need to be complicated. This worked fine for me for years until I chose to upgrade. I still don't get all the fancy terminology, and I frankly don't care. |
RE: Making sense of lighting terminology?
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| $10 shoplights do fine. Get T8's, make sure it has a ballast that actually delivers the full 32 watts. Go with either 4100K or 5000K. Phillips Alto 850 high output lamps are an excellent choice. I used to believe in warm white, but I don't use them anymore now that I've seen what they do to rooted rose cuttings (pale leaves). If you can afford some 2 mil mylar (from businesslights.com), slip some inbetween the lamps and the stock reflector, if you'd like to improve the efficiency. I actually use carpet tape to stick the mylar to the reflector. Warm white has more red component which may be important for germination, but I've never really noticed any difference. The blue component is very important for chlorophyll synthesis. The actual spectrum of the lamp is otherwise somewhat irrelevant, and CRI is completely irrelevant. Paul Mozarowski. |
RE: Making sense of lighting terminology?
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| Thanks very much for the reassurance and the suggestions! I know a lot of local gardeners but no one does their starts under lights, so it is good to have a little direction and to hear that simple _has_ worked out for folks. :) I finally found some "lighting for dummies" definitions on wikipedia, if anyone else as newbie as I am passes by this page: "Lamps are typically identified by a code such as F#T#, where F is for fluorescent, the first number indicates the power in watts (or strangely, length in inches in very long lamps), the T indicates that the shape of the bulb is tubular, and the last number is diameter in eighths of an inch. Typical diameters are T12 (1.5" or 38 mm) for residential bulbs with old magnetic ballasts, T8 (1" or 25 mm) for commercial energy-saving lamps with electronic ballasts, and T5 (5/8" or 16 mm) for very small lamps which may even operate from a battery-powered device." Temperature comes after this number. ("CW" is "cool white", "WW" is "warm white".) The higher the K number (or degrees Kelvin), the "cooler" the color temperature. Now I feel silly for freaking out. Thanks again! Jane |
RE: Making sense of lighting terminology?
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| Don't feel silly - it can be totally overwhelming at first! There are a bazillion different lights out there, and lots of super-technical discussions about which is best and why. If you're investing in a whole room full of lights and planning to grow huge full sun plants in there for 6 months of every year, it's worth learning a little more. For seed starting, or simple small houseplants, it's not necessary, and it may or may not be interesting to you. |
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