Are My Lights Sufficient?

sherribabyMarch 16, 2007

I know this will be redundant but the information overload from searching the topic was just too much!

Went to Wal Mart to buy lights yesterday. Somebody I saw on a local morning show said to get one cool and one warm light. I SO didn't know what I was doing. This is what the packaging says on what I bought...

The one I'm assuming is cool

GE F40T12 (it says residential light)

3150 lumens, 40 watts, 4100k, cri 72 (what is that?)

And warm

GE F40T12 (says kitchen and bath)

3400 lumens, 40 watts, 3000k, cri 72

If I have a shop light hanging over each row of cell packs with one warm bulb and one cool bulb (assuming they are the correct ones) is that going to be enough? the shop light is 7.5 inches deep and the cell packs are about 10.5 inches so they will be almost covered. I could certainly surround them with something white for more reflection if necessary.

Thanks for your help!


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shrubs_n_bulbs(z8/9 UK)

You'll be OK to grow your seedlings to a few inches tall, then hopefully they'll be ready to go outside. More light would be nice, you could perhaps have fitted four T8 tubes over your flat, but see how things go. You'll need to keep the T12 tubes almost touching the top of the seedlings, so plan some means of moving either the trays or the light. Adding white cards at the side is a good idea but make sure that it doesn't get too hot inside the enclosed area.

CRI you don't care about. It is a measure of how accurately the lights show different coloured objects. It standards for Colour Rendering Index. 72 is middling, it means that some colours will not show up well and the overall appearance under the lights will be a little "grey" compared to natural light or a full spectrum light such as halogen. Your seedlings will be happy enough whatever the CRI.

    Bookmark   March 16, 2007 at 12:07PM
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I use a 4' Home Depot shop light -the kind that comes with chains and all and just plugs into a three prong outlet ($8.00), then one cool bulb (approx. 60 watts) and one soft bulb (which is equ. to warm...approx. 60 watt). I mount them to a shelf and can lower and raise it as they grow just from the chains! Total cost is like 16.00 per light! I havetwo of them..I started tons of tomatoes, peppers, snapdragons, and many annuals for my baskets this way! I hand them as soon as the seeds show through the soil and turn them on 16 hours per day and taper the light to 10 hours before hardening them to put them outside! If you notice my zone, 4, I start some things a month early to get huge plants outdoors! I generally get tomatoes and peppers a month before everyone else~

Skip the grow light for 50.00 and use just a flourescent light from Home Depot!!!!!

    Bookmark   March 16, 2007 at 12:45PM
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That is exactly what I said that I have done, rdubow. Except that mine are 40 watts each. I do still want to know if it is correct to use a warm and a cool or if I should have both of the same type and if so, which one. I didn't see anything that was over 40watts.

My shop lights are able to take either a T8 or T12. What's the difference? Which is better? The wattage was in the low 30's but I can't recall the other differences.

    Bookmark   March 16, 2007 at 1:07PM
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shrubs_n_bulbs(z8/9 UK)

T8 is thinner, one inch instead of 1 1/2". This can be an advantage because you can pack the tubes closer but in your fitting there is nothing to be gained. T8 tubes are usually 32W and are rated to give out a little less light than your 40W tubes, although they may run nearer to 40W in your fitting depending on the ballast.

As for 4' 60W fluorescent tubes? Seems unlikely, check what is actually says on the tube (and the fitting for that matter).

    Bookmark   March 16, 2007 at 2:47PM
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