newbie and light question

rersoap(z6 Pittsburgh)April 1, 2005

Help, I am going to try and grow my garden by seed this year instead of buying plants. For my lights to start my tomatoes and peppers and some flowers, I am going to use two shop lights and got some phillips t8 daylight deluxe bulbs. Is this good or should I get some other lights or combination of lights? Thanks rich

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Sounds good to me, but you may want to use regular old cheapie cool white bulbs instead of the Daylight Deluxes. The Philips "deluxe" line has a lower lumen output from what I remember Zink saying. I think a standard T8/T12 cool white has about 3000 lumens of output whereas the Daylight Deluxe sits at around 2200?


    Bookmark   April 2, 2005 at 1:24AM
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jkirk3279(Z5 SW MI)

T8 lights are supposed to be brighter than T12 but you can get better and cheaper results by overdriving the fixtures.

But then, if you don't own a screwdriver, you can still help your plants by making sure they're not cold.

Mine are in the basement and I have heating pads under the peppers and tomatoes because they were growing slowly.

But the root systems seem advanced, so it's not actually a problem. Just discouraging not to see the plants get tall as fast as usual.

When I used to start seeds under regular fluoro fixtures it was often troubling. The plants weren't getting enough light, especially lettuce.

Lettuce would shoot up and then fall over. Now, under overdriven lights it does fine. I'll probably have my first salad on Sunday.

    Bookmark   April 2, 2005 at 1:31AM
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rersoap(z6 Pittsburgh)

I looked for instructions on overdriving but I cannot find them. The shop light that I got was the 732-334 from home depot. Not even sure if I can overdrive this one or not, assuming that I can find the instructions. Anyone have any experience with this model?

    Bookmark   April 2, 2005 at 9:08AM
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shrubs_n_bulbs(z8/9 UK)

"Deluxe" tubes have better extension into the far red, therefore lower lumens. PAR efficiency is virtually the same, so at least as good for plants, maybe even a bit better than a standard tube. Tube price is a bit more. Take your pick.

Not sure I would call overdriving "better" and certainly not cheaper. It is simply a way of getting more light from each single tube. Depending on the exact ballasts used, you will get something like 60%-70% more light from each tube, use roughly twice the power, and drastically shorten the life of the tube. I would only suggest overdriving if you need more light intensity from a small fixture than you can get with standard T8's without going to the trouble of T5's or an HID lamp. Otherwise, just buy more tubes.

For overdriving instructions, search back on the threads in this forum. There are some detailed descriptions and links to wiring daigrams. Don't know if that fixture is included, but the basic concept is the same assuming the ballast is suitable.

    Bookmark   April 2, 2005 at 4:24PM
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Sam (GaWd),

I never did get around to elaborating on my initial remarks on the Deluxe versions of fluorescents. I know I mentioned the reduced lumens, but I did not comment on the benefits that could be considered.

For decades the output of the traditional halophosphate phosphor was sorely lacking in red, resulting in reds being darkened, not allowing them to contrast with other colors. At the time, all of the standard lamps on the market got their basic colors (cool white, warm white, daylight) from minor variations using the exact same phosphor for each color style.

Now to get a bit technical, and I apologize for not including any graphs.

The old calcium halophosphor (Sb3+,Mn2+-activated Ca5 (PO4 )3 (Cl,F)) had two major complementary emission bands basically blue and orange-red. The blue band was due to the activator Sb3+ ions, which absorb the 254nm UV radiation from the mercury discharge, and emit a part of this energy in a band peaking near 480nm. The excitation energy is also transferred from Sb3+ to Mn2+ resulting in the orange-red Mn2+ emission peaking at about 580nm.

To get the different cool white/warm white/daylight versions, the ratio of the blue to orange emission were adjusted. Increasing Mn2+ content, for example, suppresses the blue emission and enhances the orange emission. Further, by adjusting the Cl:F ratio, the peak position of the Mn2+(the blue one) could be shifted toward the orange. If you look at a generic SPD of one of these lamps, you can see that, although it may be difficult to ignore the mercury peaks which are insignificant, but are always drawn way too hefty. (405,436,546,578nm mercury spikes)

This halophosphate composition was used in the few types of lamps commonly available at the time. The spectrum of each was quite broad, peaking at the two derived wavelengths, and unfortunately dropping off as it approached red. The efficacy of a cool-white lamp was 76 lm/W. An F40T12/CW, consuming 40 watts, put out about 3050 lumens.

All of the manufacturers used the same composition method to produce their version of CW, WW, and Daylight lamps. The CRI of the lamps was in the upper 50Âs to low 60Âs.

Then it was discovered that with the addition of a red phosphor, strontium orthophosphate, the CRI could be increased to 85. Unfortunately, the efficacy dropped to 50 lm/W, because the new phosphor used some of the same mercury emission for itÂs stimulation. This added strontium orthophosphate was the basis for ALL of the Deluxe versions of these lamps - CW, WW, and Daylight Deluxes.

The GOOD news here is that strontium orthophosphate has a peak emission of RED at 626nm, with a very broad spectral peak (120 nm wide at 50% emission). This does a good job of covering the peak red absorption spectrum of both Chlorophyll A and B in that region. For those interested in a broadened spectrum, without gaps, the Deluxe lamps will do that well. And, if you are using the 2x overdrive modified ballasts you will re-boost the lumens to the pre-deluxe levels.

The multitude of newer phosphor blends are too large to comment on, but many of the current Cool Whites with a CRI in the 70Âs actually have an initial coating of the old halophosphor, followed by an application of the tri-color phosphors. The halophosphor layer is applied first because it is more susceptible to deterioration by the mercury emissions. Hence, better overall lumen maintenance.


Using a single 2-lamp ballast to drive a single lamp (32w) results in 70% more current being used by the lamp, and about 50% more light being emitted. The ballast is sharing its two current driving circuits, resulting in 30% less current draw than if it were trying to drive 2 lamps in normal mode.

If you have 2 OD ballasts in a shoplight with 2 lamps, you are getting the same light as 3 lamps while using the current of 3.4 lamps. That is NO LESS efficient than the old magnetic ballasts are in driving a fluorescent lamp.

Since many indoor plant growers will discard their lamps early due to diminishing lumens anyhow, it is very much worth it to a lot of people. Just ask those who have tried it how much they like it. That is why I began experimenting in the first place  very excited, happy people who swore by it. Check out the forums for aquariums. That is where I first learned about the concept. Since I have experience designing my own power supplies for electronic projects, I knew what they were talking about, and did tests and compared current consumption for myself.

One thing I should note. I took some 40w lamps, which NO LONGER would light in a magnetic ballast, and put them in an overdriven fixture. VOILA! They lit brighter than when they were new. So much for quick depreciation. I got light out of otherwise dead bulbs!

The reason that the Home Depot ballast is popular in this forum is because I experimented for months with a whole slew of different electronic ballasts, both shoplight types and much heftier HO e-ballasts. I discovered that the Sunpark SL15 ballst that was inside the el-cheapo Home Depot shoplight was extremely versitile. I took current readings on all of my experiments to compare ballasts.

That SL15 ballast, in 2xOD mode, will drive an exceptional number of lamp types, from the 40,50,55w TwinTube Biaxs, to the 54wT5Âs to the 2D- 55w bulb. That ballast drives the 54wT5 with the exact current specified by the manufacturers.

By the way, I always consider ballast losses with lm/W calculations:
Magnetic ballast with 40wT12 bulb - 6 watts (0.05mA)
Electronic ballast, Rapid Start, single, non-overdriven 32wT8 bulb - 3.48 watts(0.029mA)
Electronic ballast, Instant Start, single, non-overdriven 32wT8 bulb - 2.52 watts(0.021mA)

I have had many variations of ballast and tubes burning now for over a year without any lamp going out OR ballasts going bad.

Lastly, I thought that was brave to list 10 myths of Growing Under Lights at one time. I never saw anyone dispute the HID/Fluorescent light penetration myth before. You are correct, but I would have to remember my calculus to even try to explain it to anyone.

And that heat myth is a good one to dispel. Any two different lighting systems, with the same lm/W, drawing the same wattage, will lose the same excess as heat somewhere, as you basically said.

I could comment further, but itÂs late, and I wrote too much.


    Bookmark   April 3, 2005 at 1:00AM
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shrubs_n_bulbs(z8/9 UK)

Zink, you bring up a good point in there. I'm always amazed at the number of fluorescent installations still being driven off magnetic ballasts. The older designs in particularly are very inefficient, even the best magnetic ballast is less efficient than a good electronic one, and electronic ballasts are really quite cheap nowadays.

P.S. The ballast current draw numbers should be in A, not mA, the power is still correct. Those are numbers that you very rarely find published in type large enough to read, over 10% of the power being used to keep the ballast housing warm :)

    Bookmark   April 3, 2005 at 6:18AM
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rersoap(z6 Pittsburgh)

okay, the wife is going to kill me now. I just got two of the new cheap shop lights from home depot. Took one of them apart and even though they say SL16 on the box, they had the correct SL15 inside(red,blue and yellow from the one end.) So now I have to go and get some more to get some more ballasts to overdrive. Luckily I found the link above with the directions. I wish that I had found it before. Anyway, any suggestions on the bulbs that I should be using for starting tomatoes, peppers and flowers by seed? I currently have the T8 Phillips Daylight Deluxe, should I stick with these or go with perhaps a better bulb? Shrubs n bulbs and Zink, what are your thoughts, or anyone else for that matter. By the way, while at the depot, I will look to see if they sell the SL15 ballasts seperately, but that would just be too easy. Thanks all, rich

    Bookmark   April 3, 2005 at 11:28AM
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Hey, I was only off by a factor of 1000. I guess that could affect a calculation, or two.

Tomorrow, I will go out and buy a fire extinquisher - just in case I have an actual "real-life" math error while tinkering.


    Bookmark   April 3, 2005 at 8:58PM
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rersoap(z6 Pittsburgh)

Well, I have two shop lights in overdrive mode. Pretty easy with instructions and diagrams found on net. Thanks to everyone for the help. I have 4 more shop lights ready to modify if needed. The biggest problem that I encountered was pulling the wires out of the sockets without the wires breaking. Zink, you must be a zen master because I had the worst time trying to pull them out without the wire breaking on me. Thanks again. rich

    Bookmark   April 4, 2005 at 10:58AM
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lightmaster(z8 Salem, Ore.)

QUOTE:"The biggest problem that I encountered was pulling the wires out of the sockets without the wires breaking. Zink, you must be a zen master because I had the worst time trying to pull them out without the wire breaking on me."

Try holding on to the wire while twisting the LH from side to side. Use small tugs, not big ones, That will break them off.


    Bookmark   April 4, 2005 at 9:15PM
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Zen Master? Hah! I've got a container full of sockets with broken-off wires in them.

I didn't get THAT good at it.


    Bookmark   April 4, 2005 at 11:44PM
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jkirk3279(Z5 SW MI)

"The biggest problem that I encountered was pulling the wires out of the sockets without the wires breaking. Zink, you must be a zen master because I had the worst time trying to pull them out without the wire breaking on me."

Get a large safety pin. Hold the tombstone in your hand pointing up. Tug once on the wire to be extracted, out and down slightly to expose the pinhole the wire plugs into.

Like picking a lock, use the needle of the safety pin to push back on the copper clips. Wiggle the needle, tug on the wire.

It usually pops out with a little practice.

The sole disadvantage is that once or twice I bent the copper clip inside the tombstone so I couldn't re-use the fitting.

This can be fixed. If you want to re-use that fixture, use a small slotted screwdriver to pop the plastic back off the tombstone, then you can bend the copper clip back straight. Put the back cover back on and you're set.

But with the number of tombstones we have left over it's just not that vital.

I'd like to find some better tombstones, prefferably ceramic. I sometimes have tubes flicker off and it's always the pins in the bulb not quite clicking into place correctly. Shut the power off, wiggle the tube, it comes back on.

    Bookmark   April 5, 2005 at 1:45AM
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thandiwe2(6b SW Pa)

After all this brain power I hate to admidt that I just use the cheap shop lights from home depot as is. I bring the plants up to almost touch the floresent bulbs that they come with. When they are germinating I touch the bulbs to the plastic dome to get a little heat.

I have used this system for three years on mostly veggies including eggplant and peppers. I also run a small fan. My plants are strong and highly sought at my community garden,

At one time I had a timer for the lights but when it didn't work I just left the lights on.

    Bookmark   April 17, 2005 at 12:03AM
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Absolutely! There is so much conversation around here as to exactly which bulb, ballast, reflector or what-not is necessary, you might start to think you cannot grow without all that.

Aside from growing large "high-light" plants, you can really do it all - just as you say. You can buy a good inexpensive shoplight, get the cheapest 32w or 40w cool-white bulbs on the market, and buy a fan to circulate the air - which is very important.

I have done it that way for years, and have grown GREAT looking plants. Some of the debates about exactly which color-temperature and what-not to buy is way more important to the owner than to the plant, and differences can be so incremental.

Sure, you can flood your plants with intense levels of radiation for some dandy looking growth, but you can also just buy another inexpensive shoplight, get good'n cheap cool-white bulbs, and take your plants to a higher plane of leafliness.

I consider air circulation to be one of the most important factors for healthy plants. It not only strengthens the stalk, it keeps the plant from struggling to respirate - a process which uses up available plant sugars that could be producing more leaves instead.

I once started a grow-room with junk-pile fixtures, all second-hand USED cool-white bulbs, and junkpile fans. I had enough just enough fixtures, bulbs and circulation to grow tremendously healthy plants.

Success does not require a lot of cash, or even effort, if you meet the basic needs.

My only other cheap recommendation is to get potting soil that is light, fluffy and spagnum-peat based. Plant roots love to feel unencumbered and free to roam(anthropomorphic observation). You can buy a compressed cube of that stuff, faily cheap, which will last a long time.


    Bookmark   April 17, 2005 at 2:02PM
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