Plants Slowy Dying One By One

John D'oh!

New Member
OK, here's my setup:

I've got a 6 trough NFT system with a 35-40 gallon resevior. Each trough holds 4 plants. I'm using 2 1000W HPS Hortilux lights in Vertazontal reflectors.

Here's the deal:

My plants have been flowering for 4 weeks. About 3 days ago, I noticed that the first plant in the far left trough had wilted and was basically dead. At the time I attributed it to insufficient light, because it was kind of a runt and had been overgrown by larger neighbors to the point that it was no longer getting direct light. I thought, "No big deal" and pulled the plant. As I was preparing it (hey, might as well get whatever was on it, right?), I noticed that the roots were slightly darker than normal and came apart rather easily, but they were not slimy or anything. Again, I didn't think much of it at the time.

However, now the other 2 plants in that same trough (it only had three to begin with) are wilting, and they are getting direct light. Furthermore, I noticed that another plant in the first spot of a different trough is also beginning to wilt.

There is nothing wrong with the PH or nutrient PPM.

I do have fungus knats, but they were not a problem last time.

I did add two more air pumps to the setup this time.

What could be going wrong? And, more importantly, how can I fix it before my entire crop goes belly-up?
 
I don't have a hyrdo thermometer, but I do have a heater with a thermometer in it that should keep the temp within aquarium range. It does not feel extra warm or anything...

You think I might have a gnat larvae problem? Would I be able to see them on the roots?
 
"I noticed that the roots were slightly darker than normal and came apart rather easily, but they were not slimy or anything. Again, I didn't think much of it at the time." almost sounds like they're not gettin water. water temp should be room temp 65-70's good. I've noticed knats like to live in roots, they've never really caused me a problem either i guess it depends on what type of knat. And if they're not gettin water it would make since they died so fast i mean 2 1000watts will fry the crap outa dehydrated plants
 
The fungus gnats are a problem. A huge problem. They will destroy the roots as tha larve feed as well as transmit the fungus spores to other plants root systems. They "HAVE" to be controlled. Sticky traps can help with the adults but the best way I found to kill the babies was with a super strong dose of hydrogen peroxide. When gnats are present you can guarantee that there is rotten dead plant material around. Keep everything as clean as possible and make sure you pull and remove all dead plant material from the plants and room.
Your reservoir is super small for the amount of plants you were trying to grow. this means temps will be higher as well and PH will drift more rapidly. The rule of thumb for hydro is 5 gllons of reservoir per plant.
Reservoir temp should never be higher than 70. If it does get higher fungus gnats are usually the first sign as warm water holds less oxygen and allows roots to rot easier.
 
Thanks RaceFan. Can you be more specific on how to effectively and safely apply the hydrogen peroxide treatment? I was considering getting this pesticide called Gnatrol which is supposed to be safe to use, but I would much prefer not to have to resort to that if I can get rid of the larvea with something more benign.
 
OK, I couldn't wait for a response because I am absolutely freaking out. I was going to go to the hydro place and get some 35% hydrogen peroxide, but they were closed for Memorial Day, so I went to the drugstore and got some 3%. I pulled the other 3 wilted and now dead plants, and of course the roots were simply falling apart on them. I added 1 3/4 cup of the 3% hydrogen peroxide to my 35 gallons of nutrient solution. I know that the standard 3% stuff you get at the drugstore contains a synthetic stabalizer that is toxic when consumed, so I hope I didn't do something really stupid by using it, and I am going to the hydro store tomorrow to get some of the non-stabalized 35% stuff, flush my system and start over using the right stuff. I also turned the thermostat on the heater all the way down, but I'm thinking I should probably just pull the plug on it and only use it in the winter time at the lowest temprature setting. BTW - it's easy to keep the water warm with a heater, but how to do you ensure that the water does not get too warm just from the lights? My room is pretty well ventilated, but the air temp still stays between 80 and 90 degrees, and obviously the water can get warmed up just by the ambienmt air temp, right?

Like I said, I hope I didn't just create a toxic crop by using the apothacary 3% stuff. Somebody please tell me it's going to be OK, because like I said, I am absolutely freaking out right about now.
 
Toxic stabalizer? HUH? I gargle with the crap at a 50% solution per directions on the bottle so it can't be too toxic.
The gnatrol is a great product and what I have used in the past for soil grows. It works on the larve only though. Sticky traps are still needed for the adults.
When I used the peroxide I dumped a full 3% bottle into my 30 gallon reservoir and ran the NFT system for 15 minutes then flushed and rinsed out the reservoir and nft mat which flushed the plants at the same time. I then ran it with plain water for 24 hours and then did it again with the peroxide. I wouldn't recommend anyone else do this though because peroxide can and will eat the feeder roots off and kill the plant if applied for too long in high doses. I did it to kill the larve off and it worked. It btook about a week for the plants to recover and start making new growth.
 
There is a Neem drench that you can use to add to your medium with watering. The one I use, and the one I sent to Racefan, is applied at 1ml/10 litres. This not only gets rid of all stages of fungus gnats, it also acts as a deterrent for future pest problems in your medium. As for adult gnats, the yellow sticky traps mentioned by Racefan are excellent. I use them all the time. Remember that the gnats can be a sign your medium is too wet.
 
Thanks guys! I lost a few more plants since my last post, but I think things have stabalized somewhat now (I hope), and I'm 6 weeks into flowering now, so hopefully I can nurse what's left along for another 2 weeks. The peroxide seems to be working great as far as pumping up the plants that were not affected as much by the pythium. The survivors are swelling up nicely.

My water temps were getting to around 84 freakin' degrees. I'm buying a chiller before the next round begins. It's definately worth $400 to never have to deal with this crap again!

And BTW, Racefan - I think you would have to actually consume the apothocary peroxide over a period of time to become poisened by the synthetic stabalizer, but apparently, that's what happened in the late 19th Century to people that were using it as a substitute for asprin...
 
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