A Community and Forum For Aquaponic Gardeners

T12's

I recently got some old T12 florescent lights from a friend for an indoor aquaponic system. They said they were using it to sprout seeds indoors and it failed. They are 725 lumens; the light is a GE Bright Stick. Should I use them, and what are some peoples experiences with them? Thank you in advance.

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Permalink Reply by LogicalHydro on August 21, 2011 at 3:06pm

That seems like a good starting height.. Especially for that early in growth.

Are you using magnetic or electronic ballasts? I know generally maximum ambient is about 104 degrees F/ 40 degrees C. but I'm not sure about minimum. I would assume the main problems would be the actual light bulb in cold weather, but i'm not sure.

I have heard they will start around -30 degrees C/-22 degrees F with a good ballast. but I have no proof. They warm up slowly which will be very beneficial, but cooling could be problematic under really cold temps

Permalink Reply by Vlad Jovanovic on August 21, 2011 at 5:11pm

Wow -22c thats darn cold, I'm hoping with the supplemental heating it wont get much below 2 to 5 degrees Celsius on the worst of winter weeks, but wanted to make sure just in case the air temps ever fall near freezing that they would start up ok and that the bulbs would be alright.

No, I didn't get the digital ballasts.

Yeah, I see how really fast cooling during cold temps could be problematic (for the glass, for the ballast I have no idea). I was planning on having the timer kick them on around 2:30 or 3:00AM and off then off an hour or two after the sun rose and it warmed up at least a little. So maybe that will help with the cooling down?

I find it kinda strange that minimum working temps are so hard to come by? Thanks for the info (even if it's just something that you heard).

Permalink Reply by LogicalHydro on August 21, 2011 at 7:50pm

That sounds like it will help. Yeah its pretty odd, especially since most fluorescents tell you right away what the min and max ambient temps are. Hopefully you don't encounter too many problems with them. Let me know how the setup goes.

Permalink Reply by Vlad Jovanovic on August 22, 2011 at 7:18am

Thanks, I will (at this point that's looking like early-mid October at best).

Permalink Reply by Eric Warwick on December 4, 2011 at 7:28pm

Hey guys, I want to give you all an update. I've got some good growth from my lettuce and chives (started 2 weeks ago). I use only one of the bulbs and the plants are lopsided, but it doesn't affect taste. I actually had an idea today to put a green cup over seedlings. I'll see how that pans-out. Bye.

Permalink Reply by LogicalHydro on December 4, 2011 at 9:33pm

Eric,

That sounds great. But what is the purpose of the green cups?

Permalink Reply by Eric Warwick on December 4, 2011 at 10:11pm

To filter unneeded green light, of course plants do that on their own...

LogicalHydro said:

Eric,

That sounds great. But what is the purpose of the green cups?

Permalink Reply by LogicalHydro on December 4, 2011 at 10:26pm

I'm very curious to see the results you get from this. I have no experience on filtering light with film and obtaining a desired wavelength. But, to me it seems like it could go either way.

(sorry if it's a bit unstructured thought.) a green plastic could filter out the green wavelength from the light from the bulb. But if you buy a green bulb from the store, it is essentially a regular bulb with a green film over it. The result being everything appears green. It would seem counter-productive if that were the case. A leaf absorbs every color except green so it gives off a green tint. So wouldnt a green plastic cup act the same way. It would absorb all colors except green, making it appear green.

Could you help clarify it for me

Permalink Reply by Eric Warwick on December 4, 2011 at 11:10pm

I recently remembered that plants filter it on their own. I really wanted to make a mini-greenhouse so I put a green cup on it. The chlorophyll does the job anyways, however. So, I'm not sure why I did that, but I think filtering other light could be a good idea. Anyways I'm going to have to do some investigation.

LogicalHydro said:

I'm very curious to see the results you get from this. I have no experience on filtering light with film and obtaining a desired wavelength. But, to me it seems like it could go either way.

(sorry if it's a bit unstructured thought.) a green plastic could filter out the green wavelength from the light from the bulb. But if you buy a green bulb from the store, it is essentially a regular bulb with a green film over it. The result being everything appears green. It would seem counter-productive if that were the case. A leaf absorbs every color except green so it gives off a green tint. So wouldnt a green plastic cup act the same way. It would absorb all colors except green, making it appear green.

Could you help clarify it for me

Permalink Reply by LogicalHydro on December 4, 2011 at 11:35pm

let me know what you find. Because right now I would say a blue-violet cup would be more beneficial as young plants need to absorb mostly that short wavelength. The cup would effectively "filter out" all other colors, only emitting blue-violet. Hence it appearing blue-violet. It would be the same reason HPS bulbs are used during flower. Plants need a long, red, wavelength, making an orangish, red HPS bulb most suitable.

Permalink Reply by LogicalHydro on December 4, 2011 at 11:41pm

It also makes sense why most LED lights come with red and blue bulbs. The only time you use green lights are for working at night when you don't with to disturb the plants. Because if you held the cup up to the light, you would essentially make a green light.

Permalink Reply by TCLynx on December 5, 2011 at 6:40am

It only really helps to target the specific colors of light if it actually allows you to get more of the desired color of light to the plants or if it allows you to reduce the energy required to get the same amount of light to the plants. Simply adding a filter between the light and the plants is more likely to reduce the amount of light the plants get unless you use a filter that can actually convert light energy from an undesirable wavelength into a desirable wavelength (I'm not sure that is really possible.) So unless the "green" light is actually causing the leave to warm up too much and by filtering it out you allow the leave surface to stay cooler and in a better range for photosynthesis then there really is no point in using green filters.

My experience with theatrical lighting is if you are in need of more light, don't add gel or filters since they will only reduce the amount of light that can reach the target. If you have excess light, then using filters (gel) can create good effects or help correct color temperatures but they will never get you more light.