> In compensation I will overdrive the lights to about 160% of
> original brightness by putting a second ballast in each
> fixture

can you expand on that?
I've never heard of such a thinng.

> In addition, the leaves took on a bit of a purple cast.
> This year I'm going to get a more complete micronutrient
> fertilizer.

That happened to me last year, and this year.
I *believe* cold can makes it difficult for the roots
to absorb phosphorus.
I added phosphorus to their water and gave them a bit
of warmer house and the purple quickly went away last
year and this.
I am a newb, please check my 'facts' before pursueing.

elskunkito: can you expand on that?

I knew there would be this question. There was a thread on gardenweb a couple of years ago addressing that topic. It's
gone but I have copies, only I don't know where they are just now. Guess I'll have to find them soon.
Basically, you add a ballast to the fixture and rewire it so each ballast drives one tube. The lights don't really burn
brighter but the duty cycle becomes longer, thus more light. However, the material is still available on the web
Here's a link: www.geocities.com/teeley2/overdrv1.html There's other stuff too. Google for "fluorescent overdrive".
That said, I wouldn't do it if I didn't already have all the fixtures set up and strapped together. There are commercially
available light banks that are a little better and a lot less work. They are costly but by the time you buy all the parts
you would spend almost as much anyway and still have to do the work. Try a hydroponics dealer or see the "Growing under lights" forum on Gardenweb.

@sneezer.
That's great info, thanks!

Here's the link to a copy of the original Garden Web thread from Nov 2003.

Terry Light
Oak Hill, Virginia

Here is a link that might be useful: I have found the BEST cheap flourescent ballast/fixture

First a question: How does an increase in "duty cycle" yield more light output. I'd go for it in a minute if I thought I could really get some more light output!

Next a suggestion: (For purposes of comparing seed sprouting
tecniques) Go buy a small bag of a good commercial seed sprouting mix--enough to fill one tray of cells. You can use plain Miracle Grow Potting Mix but then I'd suggest you screen out the logs and fenceposts using a 1/4" hand screen; that's how I do about 200 plants each year. Try to get the biggest cells you can for the tray insert. You can use small plastic flower pots from last years flower garden so long as you sterilize them with chlorox water then rinse.
Use a tray with a clear plastic cover;I also use a sealed bottom tray and just guard against over watering because tray bottoms with holes are such a damn mess. You need
about 3" clearance minimum between the soil at the top of
your tray cells or your little pots to give room for the plants to make a sprout. If you only have trays with holes in the bottom just line the bottom and sides with plastic film from a wastebasket or garbage bag. Fill the cells or
pots with sifted potting mix or germination mix and lightly compress. Plant 3 to 4 seeds in each spaced evenly apart,
seeds should be about 1/4" deep when fully covered.
It takes about 42 ounces of water max to nicely saturate a full tray so planted: but don't drown them. This is likely the last watering you'll need until you remove the clear plastic tray tops. You can easily pick out and transplant excess plants in each cell or pot when they are about 2" tall. Just water them in good and make a deep narrow hole for the roots and dirt carried with them during the transplanting. I use a tiny shovel about 5/8" wide I made
from the top of a veggie can to transplant. Backfill the divits made in the germination cells/pots with more potting mix.

Now compare your germination results with the method you have used in the past! By the way, when you transplant go direct to a 1 pint or 1 quart plastic cup with drain holes in the bottom. Later you can compare plant performance of the transplants with those left in the original germination cell/pot.

Here is a link i used to overdrive.

Here is a link that might be useful: overdring fluorescents

larryw:
How does an increase in "duty cycle" yield more light output.

Fluorescent lights are not "on" all the time. In effect, they pulse on and off. Duty cycle
is the amount of "on" time during a reference period. By overdriving with the method
suggested in the reference threads, you keep them "on" for a longer time during that
reference period. Hence, more light.

larryw: Next a suggestion

Well, I don't think so. Not that I disagree with you - the suggestion seems fine, and many may want to follow it. I've
used the peat pellets because they are convenient for me. I don't grow that many plants to maturity - at most a dozen
and give away a few seedlings to friends. I suppose there's no reason why I couldn't use any potting mix in cellpacks
at that stage but I just haven't. I do transplant directly to a quart plastic cup, where the plants stay until they are set
outside. My biggest concern is that I want a strong root system and I want to preserve it intact when moving
the plants. The peat pellets do that for me at that early stage. If I were doing more plants, maybe I would use a
potting mix to start but for the number I do, the pellets are not that expensive. By the way, by the time the seedlings have
their first true leaves, which is when I transplant (about the same as you) the roots have spread throughout the peat pellet
and then some and when I move them I don't lose any of it.

I don't think that a comparison of germination results between peat pellets and potting mix would mean much in this case though, of course, those who want to make such a comparison may do so. When I speak of sometimes weak germination,
I'm talking about seed viability. All my starts are done the same way and often, of 10 or 12 seeds, a couple will not
germinate and of those that do, 2 or 3 will be the strongest. Those are the ones I select to transplant and continue with.

Other wise, what you are doing and what I am doing are much the same and it seems to work for both of us.
Anyway, thanks for the suggestion. I hope some readers will be able to use it.

The "difference" I am talking about in this item is in trying a mycorrhizal inoculant. Just when, or whether, I would see a difference is unclear. But see the Fungi Perfecti website for their claims.

sneezer,

1st, thank you very much for the info on overdriving fluorescent lights. I'm a mechanical type and frankly have difficulty spelling electricity much less understanding it.
However the instructions are plain enough and I'm going to give it a try. The first trick will be finding additional ballasts for those cheapie double 40 watt tube shop lights.
Even if I have to canabalize a couple new ones it will be worth it to me.

Regarding the use of peat cubes or peat pots. Sure, if they are working for you just stay with it. I had problems in the past with them drying out on me but then I was doing a whole lot of plants and my time was limited due to a heavy travel schedule.

larryw,

In all honesty, my advice is that if you are starting from scratch, you should not do it. Frankly, it is not worth the trouble and the expense. I'm overdriving because I already have a set of lights put together and the incremental expense is not that much. Starting from ground zero with cheapie shop lights though is really not a working proposition. You can buy a very nice 6 tube, high intensity, T5 fixture for about $200. But, believe me, if you are starting where I think you are, you will spend that much and more plus all the labor and a good portion of frustration before you get anything really functional. You'd be better off, if you have a job, to work some overtime and put the money into some good lights. In a way, I regret bringing up the topic again. I only did it because I have my own list of changes I want to make this year and that is one of them. Inadvertently, I have encouraged some people to want to try, who shouldn't. This is not a matter of personal ability or anything like that, but just a result of what is available, the compromises you would have to make and the prices you would have to pay to get something acceptable. Again, I'm doing this only because I have lights that I have been using since before the really nice commercial sets became available at reasonable prices. Please take my advice and go the other direction. You will not regret it.

larryw, the HomeDepot shop lights are under 10 bucks apiece so the expense is really not an issue I think the issue is are you running out of room for an additional light fixture because overdriving a fluorescent only increases light intensity by 1 1/2 times normal so if you have room for the whole fixture you would be getting more light by using the whole thing.

Dale

Sorry but the expense is an issue, the major issue. Those ten buck lights will NOT work for overdriving. I've been there, done that.On the other hand, if you just want to use them as is, that will work. I did that too, and got good plants. You would have to use enough of them (at least 4 tubes per shelf) and expect them to go bad pretty fast. They are flimsy and the ballasts are crap but if you want a cheap stopgap measure, yes, they will work for a while.

Somebody better tell my lights that then because they are working fine.

Dale

Sneezer2,
The cheapo shop lights from Home Depot or Lowe's with the Sunpark SL15 ballast DO work! While you can't overdrive fixtures with the older magnetic ballasts (designed for T12 tubes) you can with the newer electronic ballasts used for T8 tubes.

I have four two tube overdriven fixtures I constructed and have used four seasons without any problems. I started with eight new shop lights from Home Depot which cost about $7 each in 2003.

I have not replaced the original tubes and I've not noticed any degradation in light output but I might purchase a couple of new ones prior to starting seeds this season to see if I can tell a difference.

Terry Light
Oak Hill, Virginia

Terry,

I'm very glad to hear that. Also glad to hear that you are finding cheap fixtures with an SL-15. Of course they would work. Unfortunately, I have not seen them here (near Pittsburgh) in a long time.

I do wonder, however, just what you mean by "cheap" right now. I've been looking over some of the original posts and see that they were about $6.50 in 2003. I got mine for about $15 in 2004 (and that was a special closeout). The only thing I am seeing equivalent now and for quite some time runs about $30.

The "cheap" fixtures I referred to (the ones I said wouldn't work) do sell for between $7 and $10 from time to time but they are the ones with no "box" along the top, i.e. no space for a "real" ballast just folded sheet metal, and a very tiny ballast in the end cap. I started with those about 8 years ago and, yes, they were OK for a while but they quit in about the second season (not overdriven). The fault in all of them was that tiny ballast, which I do not consider overdrivable or even repairable.

My concern with even raising this topic again is that someone may buy those $7 lights and either get in trouble or find they just don't work very well, then end up buying $30 lights anyway. That can get expensive. If you add up all the costs of getting into that situation then you might as well buy the commercial lights. Well, I know not everybody has $200 for that but I wouldn't want to spend $200 the other way either and have to go through the frustration.

By the way, I really don't see anything wrong with someone using those cheap lights to grow tomatoes. After all, this is supposed to be a forum on growing tomatoes and not on electronics. They will work, especially if you need a lot of them, but my experience is that they don't last and they are not worth enhancing in any way, either by rewiring or by using expensive tubes. But then, if you can get better ones for cheap, go ahead and I wish you all the best.

I would like to know more about what you are finding and where in terms of SL-15 fixtures. I've spent far too much time and energy over the last year traipsing through HD and seeing nothing but junk. Thanks for your input. I hope the situation has changed.

Sneezer2,
Whoops! Guess I should have clarified a bit better that it was in 2003 that I purchased the shop lights and I haven't shopped or looked for them since. And now that I think about it there is a strong possibility I bought those fixtures from Lowe's instead of Home Depot.

BTW, I let my fingers do the walking and found Sunpark sells SL15 ballasts online for $6.50.

Terry Light
Oak Hill, Virginia

Here is a link that might be useful: Sunpark Corporation

Well, guess it doesn't matter. Probably not Lowe's, at least not around here. HD, for some reason is a lot better for electrical stuff. At least here.

Yes, I have the SL-15 directly from Sunpark too.

Funny thing is though, when I started this thread I was looking for comments on everything except lights. Just let that bit slip in and look what I got! Anyway, I hope everybody is up to date now on lights.

Today I have reason to go to both Home Despot and Wallymart.
I plan on buying two bare fixtures and plan to let my eyeballs
make a highly perceptive and technically objective decision on where to buy.
If this doesn't work I will look for all possible ways to avoid accountability and place blame! Beware!

Anybody need any bare fixtures less ballasts? Such a deal I got!

Good Luck !!