Lights for starting from seed.

[Mlm1]

Wow, that is a lot of snow. It's like spring here but can't take it for granted yet.

[ChrisK]

What about CFL lights? I was thinking one could make a plywood plate, painted white and attach standard ceramic light fixtures. Would be really easy to make and wire. How many would you need for say a 4' x 2' shelf?

[Cole_Robbie]

I do that a lot, CFLs in cheap ceramic sockets. The biggest cfl I can find is either a 150 or 200 "watt equivalent" for about nine dollars. You can use shelf brackets to mount the bulb vertically and an aluminum pie pan makes a great reflector. I always cut the cords off of anything electrical I'm throwing away, so that I can use the plugs and wire for wiring lights.

[ChrisK]

How far apart do you space the fixtures?

Originally Posted by Cole_Robbie

I do that a lot, CFLs in cheap ceramic sockets. The biggest cfl I can find is either a 150 or 200 "watt equivalent" for about nine dollars. You can use shelf brackets to mount the bulb vertically and an aluminum pie pan makes a great reflector. I always cut the cords off of anything electrical I'm throwing away, so that I can use the plugs and wire for wiring lights.

[Cole_Robbie]

Well, the more the merrier, until it gets too hot. You could easily fit four bulbs over that 4x2 shelf. The more point sources of light you have, the less you will get seedlings on the edge of the shelf leaning toward the light. I think it would also work fine with just two or three bulbs.

[RayR]

Originally Posted by Hotwired

Dar, when you say most shoplights have magnetic ballasts, I would agree, assuming you're referring to existing shoplights that are currently being used. Magnetic ballasts were due to phase out in 2010. The Energy Policy Act of 2005 required a minimum ballast efficiency factor (BEF) standards. T12 inductive (magnetic) ballasts do not meet this regulation. These standards are now applied to magnetic ballasts used in various fluorescent lamps, which effectively caused the phase-out of these ballasts in new equipment in 2010. Magnetic ballasts are still widely available as replacement parts, however, almost every fixture manufacturer has switched over to electronic ballasts. I believe that China is not able to export any lights with magnetic ballasts as of 2012. I was under the impression that if you find a new fluorescent fixture with a magnetic ballast, then they are selling old inventory and are breaking the law. The cost of manufacturing an electronic ballast is a fraction of that to produce an inductive, and even cheaper if you leave out the dimmer capability, which is why there are still the cheap T12 shop lights for sale. That was my understanding, but I might be wrong.

You are right, they are still selling T12 fixtures, but they are with T12 electronic ballasts, most will not support T8 lamps. The cheap fixtures have the ballast in the end cap which is not upgradable with a standard T8 ballast.
I got an old 4ft. T12 fixture for free from a friend that had a standard magnetic ballast under the top cover. I bought a T8 electronic ballast off Ebay for cheap, installed it and changed the wiring around from the old Rapid Start configuration to Instant Start. Works great!

[ChrisK]

I've never seen the end-cap ballast type fixtures. Almost all I have from HD/Lowes have the ballasts in the body of the fixture.

What brand/model of ballast did you get from ebay? Seller?

Originally Posted by RayR

You are right, they are still selling T12 fixtures, but they are with T12 electronic ballasts, most will not support T8 lamps. The cheap fixtures have the ballast in the end cap which is not upgradable with a standard T8 ballast.
I got an old 4ft. T12 fixture for free from a friend that had a standard magnetic ballast under the top cover. I bought a T8 electronic ballast off Ebay for cheap, installed it and changed the wiring around from the old Rapid Start configuration to Instant Start. Works great!

[RayR]

Originally Posted by ChrisK

I've never seen the end-cap ballast type fixtures. Almost all I have from HD/Lowes have the ballasts in the body of the fixture.

What brand/model of ballast did you get from ebay? Seller?

Some are, some aren't. You can usually tell if it has an end-cap ballast if the tombstones are molded into the end-cap as one piece and it doesn't have a removable ballast cover, usually on top.of the fixture
I have a couple of fixtures I bought from K-Mart a few years ago for $25.00ea that have end-cap ballasts that have been working fine, but those supported both T12 & T8 lamps. Most cheaper fixtures on closeout I've seen that are T12 don't support T8 lamps.
So if you are going to buy a fixture these days whether with an end-cap ballast or standard ballast, I would make sure it is a T8 fixture since the availability of good T12 6500K Daylight lamps are drying up anyway. Lowes doesn't even have 4ft. T12 lamps anymore except 5000K Sunshine and warmer cool white lamps last time I looked.

I bought some GE UltraMax T8 2 Lamp electronic ballasts (GE232MAX-N ULTRA) from a seller last year that was installing new lighting fixtures in a building and removed the T8 ballasts from the old fixtures to sell. They only cost me about $16.00 delivered for three of them, which was a bargain compared to the price of new ones. I have some failing 4 ft. ceiling fixtures with magnetic ballasts in the basement that I want to upgrade from magnetic T12 to electronic T8, so the extra ones were a plus.

[zeroma]

Oh my goodness. How do I know if the shop lights I just purchased Sunday are magnetic or electric. I just called the store to ask the person in lighting who looked it up and I'll quote what she said to me. I'm hoping they are not old stock... and I don't know what I'm looking at even if I'd already opened up the boxes. They were only 14.99 and then there is a 5.00 rebate on each one...

"Unit IC wiring with UL listed normal power factor, electronic, class P ballis for 120 volt, 60 hertz ac operation". It is an American Fluorescent product.

I'm hoping that means made in American, not China.

[Hotwired]

I have a whole area that I setup with CFL's. I pack them pretty tight. Here's the spectral curve on a 6500K natural daylight bulb. The curves are significantly different than a Tube Fluorescent. The CFL's have a pretty broad color temperature and a spike at 6500K. I was very surprised when I ran this curve. It is more of a full spectrum bulb.


The warm white is an entirely different animal. It had a color temperature of 5000K but had a significantly narrower color range unlike the natural daylight bulb. Most fluorescent bulbs with 5000K are considered "Neutral" instead of Warm White.

[loulac]

Hello everybody

I'm new here and have to send my first post to be a full member.
I've been looking for ways to light seedlings for some time and I've just found here the answers I had been looking for. Thanks to you all !
lou

[RayR]

Originally Posted by zeroma

Oh my goodness. How do I know if the shop lights I just purchased Sunday are magnetic or electric. I just called the store to ask the person in lighting who looked it up and I'll quote what she said to me. I'm hoping they are not old stock... and I don't know what I'm looking at even if I'd already opened up the boxes. They were only 14.99 and then there is a 5.00 rebate on each one...

"Unit IC wiring with UL listed normal power factor, electronic, class P ballis for 120 volt, 60 hertz ac operation". It is an American Fluorescent product.

I'm hoping that means made in American, not China.

"Unit IC wiring with UL listed normal power factor, electronic, class P ballis for 120 volt, 60 hertz ac operation"

Zeroma, It's an electronic ballast, says so right there.
It's not likely you'll find a new fixture with a magnetic ballast as they went obsolete years ago.

[ChrisK]

Thanks for the info. When you say pack pretty tight what does that mean as far as distance center to center? What wattage do you use? The 100W equivalent are pretty inexpensive in bulk.

I'm thinking 6 CFLs for the 2' x 4' shelves. Which should be <$20 per shelf incl. the bulbs

I'm not too worried about matching the full photosyntheic spectrum since it is for short term seedling growth, but the curves are interesting. Your PAR curve doesn't match what I remember for photosynthesis rate, or am I misunderstanding what you are showing?

Originally Posted by Hotwired

I have a whole area that I setup with CFL's. I pack them pretty tight.

[zeroma]

Originally Posted by RayR

"Unit IC wiring with UL listed normal power factor, electronic, class P ballis for 120 volt, 60 hertz ac operation"

Zeroma, It's an electronic ballast, says so right there.
It's not likely you'll find a new fixture with a magnetic ballast as they went obsolete years ago.

Thanks so much RayR and all others. No more lighting questions from me now that I 'understand' much more. After I sent the question, I saw the word electronic and was 99.9% it was what I wanted.

I'm going to rip those boxes open and send in my rebait. $9.99 per light plus my lamps - I got a deal.

[Cole_Robbie]

Thanks for those graphs, Hotwired.

I haven't seen "warm white" CFLs. I have the daylight ones. My other option is "cool white." I would guess the cool white has a similar concentrated spike, but on the growth side of the spectrum instead of the flowering side.