Fluorescent Grow Lights

I'm going to try my hand at indoor vegetable gardening during the winter months. I have a T12, 40W fluorescent grow light that I want to convert to T5. I hope to use both 3000k and 6500k lamps. The local power company tells me that I can accomplish the conversion by replacing the current ballast with an electronic ballast. There are so many ballasts out there that I feel like a babe in the woods. Can anyone tell me exactly which one I need? Also, are the smaller T5 lamps going to fit my fixture?

Sorry nobody has answered yet--you might try the electrical and lighting forum since your question is more on the electricity end of things rather than the plants. That being said I would think you could use the lights you already have without changing them, people sell all sorts of fancy special bulbs and light fixtures for growing but for the average person growing plants indoors it doesn't really matter what you use, you can use any old fluorescent and it'll work fine as long as you keep the lights close enough to the plants.

Or the plants close enough to the lights... My seedlings and African Violets need to have their leaves with in an inch or 2 of the bulbs. You can get as creative or mundane as you want to accomplish that.

My SIL has the small fluorescent lights hanging every 2 feet down the wall and off the ceiling to overwinter her large plants in a small dark house. It has worked for her these last 12 years and these are just the 2' long, cheep-o flourescent lights that she has picked up at yardsales.

I am sure that the quality of light makes a difference, I just don't think it is that much of a difference.
Having said that, I am going to replace a lot of my lights with the LED ones that are now being used.

Here is the set-up for smaller plants. Shelves/lights can be raised/lowered for different sizes.

http://davesgarden.com/community/forums/t/939527/




edited because spell check is only sooo good....

This message was edited Jan 7, 2009 11:23 AM

What I found on T12 to T5 conversion may be hard to do or impossible due to the length of the bulbs (48" vs. 45.2"). Often buying a new fixture is cost effective instead of replacing the ballast. I buy the cheapest fixtures and standard cool or warm bulbs (currently running around 65 shop lights).

http://www.efficiencymaine.com/pdfs/Flouorescent-upgrades.pdf

Here is the super expensive model that is easily copied for home use:

http://indoorgardensupplies.com/large-stands-lite-carts-c-106_144_105.html

Thank you for your help, everyone. I didn't realize there was an electrical and lighting forum, but I'll be heading there next.

I have one of the [entirely too expensive] plant stands from a gardening store -- 2 shelves, 2 lights, 48" long. I used it last year for my seedlings. They looked very healthy at first, but were leggy by the second week. Only a few of them made it for the long haul. The lights were as close as I could get them without touching the plants.

Could I be doing something else wrong? I tried a growing medium that I hadn't used before. My tomato seedlings, which should have taken 8-14 days to emerge, came up in 3-4 days. Could it be that they were growing too rapidly for the amount of light?

Have you been able to grow patio tomatoes under the standard fluorescents with full spectrum lamps? I'd certainly rather not spend the money on new fixtures, but, as hcmcdole said, it will cost more to retrofit the ones I have.

Do you have 2 lights, side by side on the shelves? That is what is recommended. It sounds like your seedlings were not getting enough light.

There is one fixture with two 20W lamps. If I hang another, identical fixture next to this one, will I have enough wattage? Thanks, JuneyBug. Sherry

Doubling up will help but not for all plants. I had 4 bulbs (40 Watt) on an aquarium and it got too hot in there and was causing leaf burn so I cut back to two bulbs and everything is happy now.

How old are your bulbs? A lot of "experts" recommend changing bulbs once a year because they say the light output falls off in just a few months (but I don't buy into this due to replacing 130 bulbs each year is expensive and time consuming).

I've never grown them from seed, but I seem to remember from somewhere that tomatoes need to be on the cool side after they germinate, if they were too warm then they could get leggy even if the lighting is appropriate

Yeah, 2 fixtures per shelf. I cover the underside of the shelf with aluminum foil before I screw the light fixtures in. I mark on the foil where the screws go before I put it up there. You can use those plastic zip ties on wire shelves.

ecrane3 is right about the heat, I had never thought about it or had seedlings. When they sprout, you may want to turn on a ceiling fan or a have a fan blow gently near them to keep from heating them up too much. And not box them in with foil or mirrors like I do.

Thank you, again. The bulbs were new when I used them on last year's seedlings, so that probably wasn't the problem. I didn't know that tomatoes like it cool; I would have thought the opposite. Anyway, I'll try cooling them off a bit. I seem to have decided to give the T12 lights another go. Do the full spectrum bulbs contain enough red to support flowering plants?

Don't waste your money on full spectrum bulbs. Most folks say they have good luck with warm or cool or a mix of these two bulbs and save $$$ too. I have many plants blooming under standard bulbs (about $2 a piece).

Thank you, everyone. You've been a huge help.

You can convert from T12 to T8 by just changing the ballast and bulbs. If you go to T5, you would also have to install new end clips for the bulbs and they would in most cases have to be mounted in a different spot on the fixture due to size diference in lengths of the T5 bulbs vs. the others. I have used a combination of a warm white bulb along side of a cool white bulb and gotten good results -- you can save some money not buying the full spectrum bulbs.

Ken in Glassboro, NJ

Thank you so much, morrowsmowers. If I were to convert to T8, using one warm and one cool bulb, how much total wattage would you recommend?

Wattage is partially determined by the length of the fixtures being used. If you are using 4' fluorescent fixtures, the T8 bulbs will be 32 watts each. If you only use 2' fixtures, the wattage will be less. You need to use enough fixtures to cover the area with light.

Ken in Glassboro, NJ

Thank you, morrowsmowers. I appreciate the help.

This message was edited Jan 12, 2009 3:39 PM

I've been reading the messages on lighting. I just put my violets on an end table lamp that I put one of the new lightbulbs in. By the next day they were greener, stood up straighter, and looked really good. I'm trying to get my husband to make me a plant shelf using PVC pipe. mortswife from cold Oregon.

OK I'm new to starting seeds inside.What is the difference between regular fluorescent lights and grow fluorescent lights?

The wavelength of light is a bit different, but seedlings will do fine under regular fluorescents so there's no need to spend extra money for the grow bulbs.

Thank you!!!!!!!!