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I have a small set up that i used as a test phase to a bigger setup. It is a 40 gallon tank with 3 bluegill and some duckweed and a plastic storage tub as the grow bed up above the tank. I planted a few different tyes of plants in the hydroton grow media(lettuce, cuc's, peppers) and they all produced seedlings but seem to get about an inch tall then wilt over and die, also the duckweed is dying off in the tank. my question is is this a light issue or a issue with the fertilization of the plants? the bluegill have been in the tank for about a month and are doing fine. The lighting is 3 24" bulbs with different light variations hanging above the grow bed about 2 feet above. The cucumber seem to be leggy as well which I believe mean the light is too far away??? I want to be sure I can sustain this setup before I move on to a bigger system.

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Flouros should be as close as possible to the leaves without touching. As in 1-2" or so, and move them up daily to keep from touching. Better than flouros is to use an HID, my personal preference is CMH, ceramic metal halide, cheaper and more efficient than flouros, and will give you results. A 400 W bulb will light a 4' x 4' area from 2' away. Better yet is to throw them plants outside, it is July, after all. Full sun plants (cucumbers) will only be happy in full sun.

The seedlings wilting sound like you are running constant flood, and the water is anoxic? Need more details to help you there.

Kevin, I agree it sounds like the problem is caused by lighting to me too. 

If your bulbs are not new it may be that they have lost their efficiency.  They can look bright, but over time bulbs loose efficiency. 

You mentioned that you are using different light variations.  For growth you will want 5000K to 6500K bulbs,  This will provide light in the 700nm spectrum.

The most efficient bulbs are T5.  You will probably have to pay about $18.00 for a 24W bulb.

I built my light bar using CFL bulbs.  This was less expensive up front, but the efficiency is not quite as good as T5.

Keep the bulbs as close as you can without burning the plants, and provide good air circulation.  The air will make the stems stronger and move the heat away.   Heat is a big problem, it can dry the young plants out quickly.

yes I think having it outside would be a better option. The purpose of having it indoors now was to get it up and running for when winter comes I will already have some knowledge on the basics. So it is more of a trial then a need for vegi's at this point. I am so looking forward to not having to water a 1/2 acre garden on a daily basis.

 

A bit more info on the setup: It is somewhat of a drip system. the tube from the pump comes up to a 1/2 inch pvc pipe with holes drilled in it to water the plants. i assumed this method would give the plants enough oxygen since they are not constantly under water. I also have an air stone in the tank with a pretty good air flow.

I will try moving the lights closer to the plants to see if I get better results.

When you pull the wilted seedlings, what do the roots look like? I assume we have ruled out being too dry, after all the seeds germinated and got 2" tall, right? Are there any little worms or maggots, might need a magnifying glass? Surface watered media can attract fungus and fungus gnats, and fungus gnats can be hell to seedlings. Best if surface is dry for the top two inches, which means reworking your watering method. A photo of a problem seedling and it's roots would be helpful. What kinds of seeds failed, and what succeeded?

Bob, I cringe when I see cfl's used for anything, especially for growing. There is so much energy lost to restrike within the bulb, and for such a weak source of pinpoint light. I know we have to work with what we have got, but HID is the cheapest light for growing (including initial cost, long term cost, electricity cost, replacement cost, and environmental cost)and the most efficient source of lumens per watt. All cfl's including t-5's must be replaced every 6 months, and the making of cfl's is so toxic that may not be manufactured in the US. Meaning every cfl sends dollars to china so they can destroy their environment first. Add to that, cfl's must be disposed of as toxic waste, and legally, if one breaks, you have to call hazmat. The listed instruction for disposal request that you wrap and seal it in a plastic bag and dump it in the trash. Sorry for the rant. The cheapest price is not always the cheapest price. Mankind will be paying dearly for the mistakes of today, specifically cfl's and Toyota Prius (that's another story).

To be fair, HID lights contain mercury as well, but are much more stable and long lasting, as in 24,000 hrs. for HPS, and my CMH is rated for 30,000. If they break, almost always the mercury is contained within the bulb, and/or the arc tube.

This clip is biased for sure, but interesting.
http://www.youtube.com/watch?v=4ZalyKzXnlo&feature=youtube_gdat...
What I took home from it was that cfl's are evil, and the solution lies in better energy, not toxic ways to save energy.

I've heard CMH are kind of dangerous.  UV exposure and flammable if broken.   But two feet is amazing.  I'm interested to know more.  Do you have to ventilate the excess heat?  My indoor system is in a 10 foot by 10 foot room which is why I went with CFLs.  I did not want to deal with a lot of heat.

Jon Parr said:

Flouros should be as close as possible to the leaves without touching. As in 1-2" or so, and move them up daily to keep from touching. Better than flouros is to use an HID, my personal preference is CMH, ceramic metal halide, cheaper and more efficient than flouros, and will give you results. A 400 W bulb will light a 4' x 4' area from 2' away. Better yet is to throw them plants outside, it is July, after all. Full sun plants (cucumbers) will only be happy in full sun.

The seedlings wilting sound like you are running constant flood, and the water is anoxic? Need more details to help you there.

ok here are a few pics of what im working with. let me remind you this was a beginner setup so dont laugh too hard.

picture 1 is the tank with the duck weed and some water hycynth. the duckweed is all dying. the bubbles are air not foam.

 

picture 2 is the cucumber plants. notice the long shoots. hard to tell but the tops are shriveling and dying too.

 

pic 3 is the raft I have in the tank with lettuce. same thing here, it is shriveling.

 

Jon to answer your question, the roots look fine, no signs of rott or insects.

I still think it's lack of light but do you have sufficient nitrate?



Kevin R. said:

ok here are a few pics of what im working with. let me remind you this was a beginner setup so dont laugh

Lack of light and not enough nutrition, keep your lights on for 14 to 16 hours with a timer and put in a little fan to keep down the fungus and strengthen the stems.  Plant larger plants to begin with. Duck weed needs lots of fish poop but can live on less light.

Hi Kevin, from your description and pics it looks like there might be a number of things going on, though 'nutrition' probably isn't one of them. Generally, seedlings have have enough of what they need contained within the seed and cotyledons (those first two roundish leaves) to grow until they get their first set or two of true leaves...I've grown out many a seedling in inert media with nothing but tap/distilled/rain water larger than what you have pictured/described (duckweed notwithstanding) with no problems nutrition-wise...

The light looks way too far away for flouros, and from the looks of your pics, growing style, and mediums used, things are way, way too wet. Stems, leaves, crowns the works. Next time one of your seedlings flops over, carefully excavate the hydroton or rockwool around the area where the stem meets the roots (called the crown). You will in all likelihood notice a 'thinned out' portion of stem there. Like the outer layer of the stem has been 'eaten' away leaving only the stringy inner vascular tissue. Don't bother looking at the roots, as that type of rot can only be observed later when the plant is a bit more developed. That type of thinning, wilting and flopping over of seedlings is caused by Pythium, a big lover of overly moist conditions and one of the most economically devastating oomycetes (pythium was long ago mistakenly classified as a fungus, and some people/books still call it a fungus for some weird reason) of soil-less growing (but in soil too...). 

I've not ever had much luck starting any plants off directly in a DWC set up, because of Pythium wilt. So I start the off in net pots and hydroton but NOT in a DWC bin trough. I give them a week and a half or two, then plop them in DWC. This has worked out much better for me. 

Your rockwool cubes look totally soaked as well, and it's a very, very bad idea to have wet leaves close to any type of light, or even lights on while leaves are wet (though flouros that are too far away anyways, would probably be the least harmful scenario, still not good though)...

@Bob and Jon... CFL's suck ass for many a reason IMO. Other than being a horrible option for growing plants for some reasons Jon mentioned and considering what all is available, it seems that a great swindle has been perpetrated (once again) by industry against the environment and us. All in the name of "saving" that very same environment. CFL's from manufacture to 'end of product life' seem like an absolutely horrible product choice for nations, industry and populace to make (not to mention enforce by law). And watching the whole incandescent/CFL switchover-thing from afar was like watching a cross between a bad Monty Python skit and Orwell's 1984... I'm not even gonna get into it here...and jack Kevins thread...but +1 on the CFL comments Jon...

(one of the very small perks of living here is still being able to buy incandescent bulbs for the house...not much of a condolence to be sure, but still...ya gotta take 'em where you can...and yes, I'm aware that parts of that last paragraph are rather silly, because everyone knows that there is no such thing as a bad Monty Python skit)...

 

Thanks for steering me toward the CMH lights.  I'll check them out and be ready for next winter.

CMH are not necessarily the best, but they are my favorite. MH emit blue light for veg, HPS emit red light for flowering, and CMH emit full white beautiful spectrum, including UV. Photosynthesis uses a fairly narrow spectrum of the blue and the red, and non at all in the green, in fact reflecting it, which is why plants are green. The jury is still out on how exactly UV is used, but side by side comparisons show healthier plants when a little UV is added, IDK. I do know that HPS are cheaper, about $20 and on the shelf at Home D for a 400W, as opposed to $50 for a CMH 400W. Bob, and Kevin, you will be amazed how cool HID lights are compared to flouros. The bulb itself is hot, yes, but the total heat generated per watt is less, and a vertical CMH bulb needs no cooling at all, not even a fan, as the natural convection draws a cooling air current upwards past the bulb. I pay $.45 per KWH, so efficiency is paramount, meaning no reflectors or glass to suck lumens. I hang a vertical bare bulb, and situate my plants around it in zip-grow style towers. Ideally, I don't want a single photon striking anything but plant. Is the UV dangerous from a CMH? Yes, probably, just as dangerous as it is from the sun. I have never noticed any discomfort, but I am in the sun working every day anyway. I've read that sensitive people advise wearing sunglasses, long sleeves, or even sunscreen if working around bare bulbs for extended periods of time. I have them lighting up my whole shop, but they are in closed fixtures with a glass panel, which blocks the UV.

I get my CMH here, and ballasts, and sockets are available for about $15 at your local head shop. http://advancedtechlighting.com/cdmed18.htm For flat grows like Bob and Kevin have, you'll want to add a wing style reflector to bounce light back down to the plants. The linked site also show some pictures of failed bulbs, and how the arc tube remains contained. The Phillips brand they sell are rated for open fixtures, a big plus for bare bulbers like myself.

Vlad, I agree, probably pythium, and the bad Monty Pythons are the best :)

Kevin, thanks for the pics, that helps a lot. Too little light for sure, too wet and humid for sure (there is water beaded and dripping off the flouros), and ditch the rockwool IMO. Start your plants in a sunny window or porch, or simply in a flat under flouros (flouros DO work fantastic for starting seeds, nice and close, and all that heat is reflected down to warm the soil (I start in compost, or rapid rooters if you want to stay soiless)

Thanks Guys. The coments helped alot. I think im going to redesign my whole grow bed to something a bit different. I may try and steal a couple ideas from some of the pictures on the forum.

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