building a single indoor tomato setup, hps or tube fluorescent?
 

hey everyone.. im looking to start growing a tomato plant indoors... im going deep water culture in a 5 gallon bucket and an aquarium air pump to oxygenate the solution...

anyway, ive been thinking of grow lights.. this plant will be about 4 feet high, trimmed if neccessary and will be grown indoors with a wall on 3 sides of it to reflect more light onto the plant, the bulbs will be mounted from the side to cover more surface area

one option is a 100w HPS bulb, 9,500 lumens of about a 6500 color temperature, since the light is a more localized source it would have to be placed further away to cover the entire side of the plant and to prevent the plant from being burnt

my other option is two 48" long t5 grow lights, i can get these in any color temperature it seems, and they produce about 5,000 lumens each at 54w, so 108w and about 10,000 lumens with this setup... also, i can position them closer since the longer bulbs will be able to reach the top and bottom of the plant, and lower heat would prevent burning, also, a 2x 48" tube light fixture is cheaper than an HPS ballast, and easier to replace

so, same color temperature, roughly the same lumens, and roughly the same cost in power... should i take the benefits of the longer bulbs closer to the plant and go with the fluorescent setup?

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I can't see either way as working. Tomato plants need lots of light and I don't think 100 Watts will work.

Let me know if I'm wrong.

I use 1000 Watts HPS for about four plants and that will grow about 5 foot plants.

well, thats why i was considering the tube fluorescent lights.. at the same wattage they produce a bit more lumens in a color temperature better suited for the plant, and i can also move them much closer to the plant because of lower heat and longer bulbs making less watts go much further, also having them in a 3 sided box to reflect the extra light that would usually be wasted to the other sides of the plant, making the 100 watts seem more like 200+

The owner of Hydro Gardens{Tomatoes are his specialty}once told me that a tomato plant needs at least 1000 candlelight.
My T5 florescent lamp with 8 tubes gives off about 300 candlelight's about 10 inches away, And that rapidly diminishes the further you move away.Even with reflected walls.
The first time I grew tomatoes i used 400 W. HPS and that did pretty well. Then I decided to go to 1000 W
I think I've read that you need 40watts of light per square foot would be okay but 50 or 60 would be better.

Sorry I said that wrong my florescent gives off 3000 candlelight somewhere around 10 inches.
I can't measure them right now because the lights are off. But when they come on at nine o'clock tonight I will post more accurate measurements.
Also that T5 gives off a lot more heat than people think so you cannot get real close to them.

Okay I just measured my t5 W/8tubes, I was way off.
I get 3000 candlelight if the meter is right next to the florescent light.
I get 2000 candlelight at 8 inches away.
I get 1000 candlelight at 15 inches away.
My plants are about 20 inches wide.
I don't see how that can work for you but if you try please report back.

animus_divinus
I agree with frnz571. Neither one, the T5 fixture (even with two bulbs), or a single 100 watt HPS will produce much of anything in the way of fruit. Either way you'll wind up with spindly plants with little to no fruit. The fruit that does develop will be way under size (and may not even taste good). Keep in mind that just comparing lumens bulb for bulb (HPS to florescent) is like comparing lamp oil to jet fuel (not comparable). It's not what the bulb can put out at the glass/bulb surface, it's what the leaves receive that's usable to the plant. Even though florescent lights can be placed closer to the plant because of less heat buildup, that still dosen't offset the usable light "drop off" the plants actually wind up getting from the light source (even trying to reflect it). I'm not sure what variety's of tomato's your planing to grow, but if they aren't expected to be larger than 3-4 feet they must be bush variety. Even so, 1-100 watt HPS bulb again won't be adequate if you want it to produce well. Bottom line your better going with HPS, and ventilating if necessary. For more even coverage of light you can use multiple 100 watt HPS bulbs, instead of one 300-400 watt bulb.

P.S.
Thanks frnz571, that's a great example of the light drop off. Even if the florescent bulb was touching one side off the plant (at the bulb surface), the leaves less than 1-1/2 feet away (18 inches) are receiving about 1/3 the usable light. That dosen't even take into account light shading from the plant foliage.

Do you happen to know what would be the equatable lumens per square foot? 40W flourescent and 40W HPS are quite different.

Your right Swainer, I'm sure florescent light would be different.
What I was reading was probably referring to high-pressure sodium only.

I would not know how to apply that to lumens.