I would suggest a either a 400 or 250 watt Metal Halide. A 400 watt light is good for growing in a 5x5 foot area (25 square feet) while a 250 watt will be adequate for a 3x3 space. May I suggest trying a different technique for your bathtub?

Fill the tub with water. Buy a strong air pump and two long air stones. Place the stones in the middle of the tub. Cut a sheet of plywood to cover the top of your tub. Cut holes in the plywood where your plants will go. Buy a cheap hydroponic fertilizer and you will find that your plants will grow twice as fast as in soil. Its a lot of fun!

Paul

I didn't know if I could use the tub as a Hydropoic. I have only seen the ones that look like they are made out of pipe. Do you have a link where I can see this made.

I will look to see what I can find.

This might change the topic a bit. I was thinking about how, too experience change among the lines of chlorophyl in plants, they need certain amounts of uv. between 400-500 and about 600-700 nanometers. If you found an ozone machine that puts off more than the usual 200 nanometers and in the chlorophyl reaction region, would the plants not need light? And maybe if these questions might be possible, then would it be possible to create "Albino" sub cultures?

Hi Warren, If you care to check it out, there is a forum devoted to growing under lights. My experience with growing under lights was both good and bad. The problem was that I live in SW Florida, and keeping the room cool during the warm months was not easy. However, it was winter when I started, and initial results were great. I bought a 1000 W metal halide light system with a special warm tone bulb that gave off light with wavelengths suited for both growth and flowering. I have also used a 250 W high pressure sodium light from Lowels hardware with good results. Stay away from mecury vapor lights, they have the wrong kind of light for plants to grow. When I used the 1000 watt metal halide light, I was able to supply suitable light for an area roughly the size you have available. The reflector assembly was suspended from light weight chain using S clips so that the reflector assembly could be raised as the plants grew higher. My crop was hot peppers, and they grew to about the same size as your tomato plants. There were some drawbacks using the 1KW MH (1000 watt metal halide) system. First, there was the high heat given off by the lamp itself. My refelector had provissions built in for an exhaust system using regular cloths dryer ducting. I never did use it though. Instead, I mounted a window fan in a window to exhaust the warm air with another window cracked open for cool air intake. One other problem that finally caused me to stop using the HP light was the fact that police heliocopters were flying all around using infored systems to locate pot grow houses, and I did not care to have the DEA crashing through my door in the middle of the night. I found that by mounting my 250 W HPS (high pressure sodium lamp on the wall, and using bricks to raise the plant containers up to within 12 inches of the lamp, (plant tops) provided very good results. As the plants grew taller, I lowered the containers to maintain the 12 inch spacing. I later transplanted the plants outside when they were ready to flower. I used a simple cheap timer from Lowels to give the plants about 18 hours of light per day. I fed the plants using miricle grow pre mixing the water into gallon milk jugs. I would also recommend that you take a look at the grower that is featured in the posting about Boc Choy. It is still a current posting very near your posting where the grow light being used is a florescent lamp array. I really think that if you mounted florescent fixtures onto a vertical post, say a 2"X2" post set into concrete inside a coffee can, it could be moved around easily where needed and would sustain the plants from top to bottom with light. You do not need special florecent lamps, regular ones will do just fine. Plants can rub right up against the bulbs without being damaged. Lastly, for tomatos, I would say that the groing pots should be 3 to 5 gallon size with lots of gravel in the mix to promote fast drainage. Holes in the bottom side will allow the excess water to drain out eaisly. good luck, chuck