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Flourescent lights

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Old 07-28-2011, 09:59 PM
jamromhem jamromhem is offline
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Default Flourescent lights

I was doing some research on fluorescent lights the past few days and felt I should share some of it.

This is my first post on the Forum BTW, So hello to all. lol

I am new to hydroponics and spend a lot of time researching on ways to do things to try to get as much information as I can on the subject.

This is something some might know already and this is not a direct reply to anyone specifically. It is just a knowledge find I felt would be useful to some to share.

People often use 3 "flavors" of fluorescents.


From what I have seen.

My research on what I the plants need for their growth is that 5000K lights, while sufficient, are not optimal for plant growth. They lack most of the light that Chlorophyll A requires and barely touches part of what it needs.

6500K is a preferable "temp" for the vegetative growth of the plants, as it covers more of the spectrum of the plants photosynthesis.

2700k Is still fine for flowering and "fruiting".

I have seen people say they are using 8000K lights. Those are way overpriced and don't contribute much to the plant more than 6500k lights from what studies have shown as the wavelengths that plants use.

I hope this was informative to some, and will be useful to anyone wanting a little bit of information on Fluorescent light "temps".

I tried to format it in a way that would be good for some of the active members as well. *Waves at GPS* I have probably read about 1/4 of the forum before posting my first post lol.

Last edited by jamromhem; 07-28-2011 at 10:06 PM. Reason: Spell Check
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Old 07-31-2011, 12:48 PM
furniture@finewoodstudio. furniture@finewoodstudio. is offline
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Default good resource

I had a like question in the prior post as to what light is required to ripen fruit. In my research I came across this link. As the person to replied to my question said if the correct spectrum and amount of light that is needed. The only change I make to the article is that tomatoes required 40watts/sq ft not the 30 that is mentioned.

The article is "fluorescent lights for Plant Growth: by Wayne Vandre, Horticulture Specialist" Cool House Hydroponics - Fluorescent Lights for Plant Growth
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Old 07-31-2011, 01:37 PM
jamromhem jamromhem is offline
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ok.. Read through the article and I might be able to expand on it in terms we use a bit more often.

I am using one of my 2600K bulbs as an example in this.

My bulbs use about 32W and provide 2475 lumens. I pulled up a few calculators, and that comes out to about 230 foot candles (x4 for 4 ft) equalls 920 ft candles.

My bulbs are obviously more efficient than the ones that they use in the example. The one in the example provides about 20 ftcandles per W and mine about 28 per watt.

So, needing 40 W per ft for tomatoes with their bulbs would mean to those using 77 lumen per watt bulb (compared to their 58) could use around 30W per ft. So you would only need 3 tubes running instead of 4. That being said I think the configuration of your light will make a huge difference.

If you are hanging your lights above the tomato plant I think you should stick with the 4 or more bulbs... If you are running your lights up the length of the plant you might just be able to get away with 3 T8 bulbs.

This is in no way a proven fact. Though I have seen people grow tomatoes with a lot less light than most people use, by having their lights run the length of the plant rather than shine down on it. Running the light virtically lets you maximize the light use rather than the light being almost worthless to the plant by time it hits the bottom leaves, or reflects off of something else to get to them. Light from flourescents loses about 1/4 of it's strength per foot, past the first foot. I hope my thoughts on the artical are useful to some :P This was more of a think it out post than a already had it all written down and practiced and known. and I hope that I was able to help someone atleast think about their flourescents a bit to try to find a more efficient use of them.

Last edited by jamromhem; 07-31-2011 at 02:11 PM.
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Old 08-01-2011, 12:04 AM
T'Mater T'Mater is offline
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All i ask is plz make sure to post pic's. If you'll look i made a post cause i couldn't ever get my plant's to even start growing flower's and my plants were huge. I prolly didn't wait long enough (i'm pretty impatient) after i changed my bulbs, so i moved my indoor to outdoor and all i can say is what a difference true lighting can be.

Will be very interested in seeing how well you get your set up to work. Also if you read through my post about not getting blooms, i think GPS not 100% sure tho. anyway someone posted a few links to some video's on a guy that was growing all kinds of neat stuff indoors with lighting.
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Old 08-01-2011, 01:06 AM
jamromhem jamromhem is offline
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I am insterested to see about it as well.. I have seen many videos on youtube showing people getting a good tomato crop off of flourescents in a basement. I will be using flourescents on my tomatoes, but I havent gotten them going yet.

Some of my tomatoes will be both flourescence and natural mixed, and others will be just flourescent lights with whatevery natural happens to bounce over to them from the window. I live in an apartment so I have to use artificial lighting where there isnt enough natural. The tomatoes will be getting started here in a bit. I will probably be starting about 5 different types of indeterminates when I get it all going. I will be posting pics as much as I can along the way.

I have also seen a lot of people have blossom drop from having the nutrients too high as well as temerature problems. There are a ton of things that can cause the tomatoes not to produce... I will keep you updated when I get my tomatoes going. It is still probably a week or two before I can even try to show you anything of use though. If not longer
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Old 08-05-2011, 04:49 PM
crad crad is offline
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cool another person who wants to grow indoors. you are correct on couple of things. I got 8000K bulbs from menards for less then dollar difference from 6500K. I actually have measure the foot candles and have 980ft candles on the pipes. I mixed my tomatoes and peppers together and hopefully this weekend I get them separated.

I have not even started mixing the light colors and have some peppers growing but no tomatoes. I have designed a light rack for putting the lights vertically and facing one another I will actually have to buy a better quality meter as it maxes my out. but you assume tomatoes will only be 4" high my are taller and i am starting to trim the tops as well as the roots.

now my physical light costs are starting to get expensive so I am back at what GPS says you need to use HID I am trying to save costs as HID are spendy to burn and they increase cooling costs and should lower heating costs.

The real question is can I recover the costs in vegetable production. I will not be able to tell you that until spring. I am hoping to start building our green house(s) this fall yet.

I am just getting out of bed as my shifts have been change to compensate for an injury at work so this is off the top of my head. GPS has been correct more then once on here so he is good resource. nice to meet you jamromhem.
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Old 08-05-2011, 05:54 PM
jamromhem jamromhem is offline
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it is a pleasure to meet you as well. I have little to add as far as crop production and so on yet. I am on teh fence about HIDs due to their initial investment and heat increasing. I am growing in my house and in florida I am not wanting to pay too much more for cooling lol.. It is not as bad is GPS for cooling, but I don't like to spend more than needed.

I am currently using 2x 6500k@32W each, and 2x 5000k@32W each on my 6ft lettuce settup. It is set up to expand to 3 6ft 4x4 vinyl posts. I only have 1 in there at the moment. I have only been running it for a couple days and have little to show as far as plants :P a couple 1 inch tall lettuce that are in shock from being put in the STG cube (I am testing them. I hate fiberglass and decided to try not to use rockwool. I used to work in a fiberglass plant and went from impervious to it "not feeling it" to hyper sensitive lol)

I currently have a few tiny lettuce, a tomato seed starting to push a root, a lettuce seed pushing a root, and a few other seeds that are getting wet lol..

I am hoping to get more from the flourescents even if I have to run a little more by taking advantage of being able to have them stretch over a long area, and their long life/low power usage.

I am currently using 128W for 10k lumens (more calculations in my previous post) over a 4ft area. I am thinking this would be less than favorable to try to replicate with HID lights. The investment/running costs would be significantly higher for a non flowering plant.

I am going to be testing tomatos later and each plant will probably have some 400W each. (3 walls of 128W settups surrounding the plants). I will have multiple breeds of tomatoes near eachother and don't want cross polination so they will have isolation booths and only share the nutrient flow.

I will be stepping up the lighting little by little to see what the plant requires. starting at about 128W a plant and slowly step it up as the plants tell me what they want. I will probably do a test booth with a full settup and then build a booth with the custom light requirements for the plant.
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Old 08-08-2011, 01:17 PM
crad crad is offline
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Okay I have a little more time for this one now. If you did not know lighting is one of the means I use to feed my family.
Lighting is a very cool knowledge area to learn. So if you research lighting then you know the 7 colors of the spectrum correct? If not let me help you remember, red, orange, yellow, green, blue, indigo and violet these colors never change order either.
Now some other terms we need to know here are,
1. Fluorescent Lamp: A high efficiency lamp utilizing an electric discharge through low pressure mercury vapor to produce ultra-violet (UV) energy. The UV excites phosphor materials applied as a thin layer on the inside of a glass tube which makes up the structure of the lamp. The phosphors transform the UV to visible light.
2. Full Spectrum Lighting: A marketing term, typically associated with light sources that are similar to some forms of natural daylight (5000K and above, 90+ CRI), but sometimes more broadly used for lamps that have a smooth and continuous color spectrum.
3. Kilowatt Hour (kWh): The standard measure of electrical energy and the typical billing unit used by electrical utilities for electricity use. A 100-watt lamp operated for 10 hours consumes 1000 watt-hours (100 x 10) or one kilowatt-hour. If the utility charges $.10/kWh, then the electricity cost for the 10 hours of operation would be 10 cents (1 x $.10)
4. Lumen: A measure of the luminous flux or quantity of light emitted by a source. For example, a dinner candle provides about 12 lumens. A 60-watt Soft White incandescent lamp provides about 840 lumens.
5. Lumen Maintenance: A measure of how well a lamp maintains its light output over time. It may be expressed numerically or as a graph of light output vs. time.
6. Lumens Per Watt (lpW): A ratio expressing the luminous efficacy of a light source.
7. Typical lamp efficacies:
• Thomas Edison's first lamp — 1.4 lpW
• Incandescent lamps — 10-40
• Halogen incandescent lamps — 20-45
• Fluorescent lamps — 35-105
• Mercury lamps — 50-60
• Metal halide lamps — 60-120
• High-pressure sodium lamps — 60-140
8. note: The values above for discharge lamps do not include the effect of the ballasts, which must be used with those lamps. Taking ballast losses into account reduces "system" or lamp-ballast efficacies typically by 10-20% depending upon the type of ballast used.
9. Mean Lumens: The average light output of a lamp over its rated life. Based on the shape of the lumen depreciation curve, for fluorescent and metal halide lamps, mean lumens are measured at 40% of rated lamp life. For mercury, high-pressure sodium and incandescent lamps, mean lumen ratings refer to lumens at 50% of rated lamp life. See Lumen Maintenance.
10. Power Factor (PF): A measure of the phase difference between voltage and current drawn by an electrical device, such as a ballast or motor. Power factors can range from 0 to 1.0, with 1.0 being ideal. Power factor is sometimes expressed as a percent. Incandescent lamps have power factors close to 1.0 because they are simple "resistive" loads. The power factor of a fluorescent and HID lamp system is determined by the ballast used. "High" power factor usually means a rating of 0.9 or greater. Power companies may penalize users for using low power factor devices.
11. Rated Lamp Life
For most lamp types, rated lamp life is the length of time of a statistically large sample between first use and the point when 50% of the lamps have died. It is possible to define "useful life" of a lamp based on practical considerations involving lumen depreciation and color shift.
12. Watt
A unit of electrical power. Lamps are rated in watts to indicate the rate at which they consume energy. See Kilowatt Hour.

Couple of pet peeves here, please recycle your florescent lamp including CFL’s they contain the same amount of mercury that t-8 lamps do.
Okay now for the whole issue I started here.
I chose 8000k because they are the best full spectrum bulb I could buy in a T-8 bulb. I have peppers in bloom and peppers being produced. They are horizontally and as pointed out the light is wrong for the tomatoes I believe I need to put them vertically and am in the process of that. I also am going to include some red, orange, yellow, green spectrum on them in the form of a CFL lamp in a heat lamp assembly shining directly on the tomatoes. I am looking for a 2700 to 4100k (red 2700, orange 3000, yellow3500, green 4100) bulb with a CFL rating of 50 plus watts. Now you are starting to run up costs.
Now HID is upfront expensive plus spectrum dependant on a specific bulb. Their lumen maintenance is quicker then florescent a whole other issue. So once your lights reach that 50% area they need to be replaced as you are paying full price for a light giving 50% of its capability we will not be able to tell it with out a meter but our plants will. Now as our lamps decrease so does our color rendering and our lumen output but our operating costs stay the same as when they were new. I threw the power factor in there for your mathematical consideration as it is a factor on your power bill.
I have put this out there for your personal use and I hope it helps you in choose the correct lighting for your growing needs. I will touch on LED lighting at a different time.

Last edited by crad; 08-08-2011 at 01:27 PM. Reason: edited for color and grammar.
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Old 12-26-2011, 03:53 AM
directlight directlight is offline
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can i use a fluorescent bulb from home depot or lowes i heard u can use a 6500k for uvb is this true?
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Old 12-26-2011, 07:43 AM
GpsFrontier GpsFrontier is offline
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As the light salesman that you are, I would think you already know the answer to your question. But for now I'll assume you are new to the world of growing plants hydroponically. So to answer, the question posed is two general.

First, as a light salesman I know you are very well antiquated with the florescent lights sold at Lowe's/Home Dept, and must know there is no difference between those florescent lights, and those sold directly by light manufactures. So the question posed about if using lights sold at Lowe's/Home Dept will work is basically invalid, because it not about where you buy them from. If that was your question, buy them from Lowe's and or Home Dept, not from you and your suppliers.

If that wasn't your question, be more specific about the type of setup you plan to grow with, where they will be growing, the space you have available, as well as what type of plants and how many you plan to grow?
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Old 02-02-2012, 08:03 PM
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Originally Posted by directlight View Post
can i use a fluorescent bulb from home depot or lowes i heard u can use a 6500k for uvb is this true?
Something tells me that you've read this answer already, but here goes:

A lot of people use a grow bulb for the benefit of their plants... but these bulbs don't provid the chameleon with UV. You can use one of these grow bulbs from home depot IN ADDITION to a UVB bulb, such as a reptisun 5.0 or a reptiglow 5.0
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Old 10-30-2018, 11:48 AM
LGWayne LGWayne is offline
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Default Jiffy Adjustable Light

Check out the Jiffy light with adjustable stand and timer


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