Im not an expert at growing with hydroponics, but I believe that your problem is one of the following:

a) you have a mold or disease spreading through your roots

b) the nutrients you used were too strong (you used too much)

c) the water you used had too much particulates in it and when mixed with the nutrients, the pH either got too high or too low.

To fix your problem I recommend the following:

First, add 1 tablespoon of hydrogen peroxide to your system. This will help sanitize the water/pump/reservoir/ whatever is in the system your running. Allow the H2O2 (hydrogen peroxide) to work its magic for 10 minutes. After this, drain your system. Fill halfway with water and use another tablespoon of hydrogen peroxide again. Drain as you did the first time.

Now check and make sure that there are no loose or dead roots in the system. If there is throw them away. If you see any moldy roots or leaves, cut them now.

Use your nutrients again making sure that the proper amount is used and try and use the cleanest water possible (well water and some city tap water has a lot of particulates which can directly affect your pH level).

Also you may want to make sure your environmental conditions are correct... make sure the temperature in the grow area is between 72 - 80 degrees F. Also, plants prefer the humidity between 40-60 % so keep that in mind. Last but not least, make sure your water temperature is not getting too hot.

Those steps should fix your problem stevey.

If you have city water you must let the water sit out for 24 hours to dechlorinate. If you use 3% hydrogen peroxide available at any store use more then 1 tablespoon. Use a cup. Right now, Add h202 to the current water. Get new water, set it out. 24 hours later drain your current water and add the new water add h2o2.
If you start using h202 continue using it. The current brown roots are hopeless but should hold the plants over until new ones grow.

I've also, for a very very very bad brown root problem soaked the roots in only 3% h2o2 for about 30 minutes. Then pulled away (easily) brown roots. The plants may wilt a little but will come back. Do the same a second time the next day. Only do this if there is no hope. The plants i had to do this too would have died but now they have peppers and all white roots!

I don't measure anymore I just open the lid and splash some in every couple of days.

I'm gonna go check the pH, and splash in some H2O2.

I did just recently up the nutrient concentration. Maby it's still to much. I was just following the product reccomendations.

Thanks all!

When I checked, pH had shot up to 8.2 ish. Not sure how.

When I added some pH down, it shot down to 4.0. :) Ooops.

I dumped the solution and started again. I'll check it again tonight. I don't have any more H2O2. Is it still a good idea to add some to the water??

Yes, I would just to help sanitize the system. It wont hurt ya to that's for sure. Always better off safe than sorry I say!

very low chlorine levels can be used to help without hurting the roots. something in the range of 0.5ppm, I believe. just for comparison, 5ppm of bleach is, I believe (again), 1/4tsp per 5 gallons. If you only have access to a swimming pool chlorine test, you'll have to mix a 5ppm according to the test then cut it 1 in 9 with non chlorinated water to get 0.5. pool test kits don't measure that low.

I cut off some dead/dying leaves before I left for work.

I'm hoping it'll start to come back. Assuming the pH was the problem, how long will it take to bounce back?

Can you take some pics to give us a visual?

I can. I'm not sure how to pose them here. I guess I have to put them on image shack or something?

I have to ask. Did you remove it from it's container. I mean just to look at those silky white roots. You could have done everything right but change the placement of those roots and how they got their oxygen. Root death. That's why I have a clear stripe running down my pods so i can avoid that problem. Rules I go by nutrient problems show up in the stems and the top. Micronutrient show on the leaf edges and veins. Epsum salt lack of color. Ph first shows in wilting. Browning leaf edges and between veins shows root death. Any two of those together tells you whether the plants is worth saving.

in order to change the solution I took the whole thing out of the container, i figure for about 3-4 minutes. It seems as though it's the older leaves loosing color.

The pH is now stabalised at about 6, perhaps a little higher. So long as it's not 8, that'll keep the plants happy yes? Perhaps not an optimal 5.8... but liveable.

stevey your not listening. You changed the oxygen matrix on how the roots receive their oxygen. Those roots are going to die. Even if you charge up the oxygen supply it won't help. I'm not trying to rain on your parade but until the plant adjusts by growing new roots you'll lose alot of the old. It has nothing to do with the ph.

Those roots? Are recovering now thanks to the pH being corrected? Still a tinge brown, but not dead as far as I can tell.

I've never heard of plant roots having an oxygen matrix, nor that they can't be disturbed...

Can anyone else confirm or deny any of this? I really think it's the pH here. pH of over 8 is just too high.. that's 100 times more basic then they prefer. A big amount.

I could be mistaken, but at a pH above 8, iron availability really falls off. Without iron, the leaves don't produce much/any chlorphyl. Without clorophyl.. there is no food sugar for the plant to run on... bad things start happening.

But interestingly... older leaves start turning white.. which is exactly what happened to me.

Perhaps disturbing it didn't help... but the pH was a problem...

@georgeiii,"stevey your not listening" That's the pot calling the kettle black.

stevey,I don't know about any oxygen matrix(try to google that), but it sounds like you need to figure out why your water got up to 8+PH. That seems to be the thing out of place? You upped your nutrients with your PH out of wack and the nutrient salts locked up on your roots, turning them brown. No worries, just flush your plants roots with purified water and try to keep the PH around 6. I can't remember, what kind of system are your peppers in?

yeah stevey, change something else. The problem here is you couldn't just look at the plant and tell what was wrong. So what did you do? You got nervous. You ran for the beakers and flasks. You took everybody elses advice but question mine. Haahaa you didn't even bother to ask what a oxygen matrix was. Or how I knew that you took the plant out. I could have told you in a half hour that there was a problem just by looking at those hairs. And urban it's not
"@georgeiii,"stevey your not listening" That's the pot calling the kettle black"

it's "Lead, Stand or Follow" and your just standing still.

Thanks for the tip georgey. Your right on target, as usual?

The pH was adjusted down initially, but it ran way up in a matter of about a day. The lettuce was the same when i checked it, but the lettuce is fine. And the lettuce was removed from the system as well.

I've lowered the pH of both systems to around 6 and am now checking daily.

Also: i'm pretty sure the professional growers move stuff from pond to pond in hydroponics without ill effects georgii..

But i'm not a top hydroponic grower(no where close), and i'm interested in learning more, so tell me what an oxygen matrix is georgii.. I googled it and found nothing.

WOW Georgie! Your comments have been very rude to say the least. I believe that stevey has followed proper steps in doing what he could to save his plant roots... You have to take roots out of water in order to drain some systems... which doesn't kill roots unless you leave them out for longer than say 5+ minutes.

Anyways, im glad that your plants seem to be recooperating stevey! If the problem persists I would think about getting a different supply of water or a water filter.. chlorine or other "hard" materials in your water supply could be the problem. Where does your water come from?

My water is just city water. Out of the tap it is highly basic, with a pH of around 8.3.

I think what happened is that there was some sort of buffering thing going on. When I tried to adjust the second time, I added about .5 ml of phosphoric acid (it normally take 3.5ml to adjust from pH 8 to 6), and saw the pH shoot from 8 to below 4. So I would guess that the initial acid almost, but not quite, completely destroyed the buffering ability.

In the future I hope to solve this problem by prepping the water and aerating it several days in advance of future nutrient changes. I'm also doing much more frequent pH checks. The peppers are doing much better, and once the pH was adjusted in my lettuce, they responded with massive growth again, a whole wack of new leaves, and evaporating nearly 4L out of my 25l tank in 2 days (a new record for usage).

Thanks everyone for your help. It's a relief knowing i have access to people who know whats going on. Reading about stuff on the internet is no substitute for having real life experience with systems.

I agree Stevey, I have learned so much just by reading this thread and others like it. I think you've done everything right too, it sounds like. Trial and error my friend.
~~Cheri~~

Hey stevey, 8.3 is pretty high to start with. Your having to add more PH down and that's raising your ppm, which restricts how much nutrient you can add to get to your desired level. I guess what I'm trying to say is, you add your tap water and PH down together and your starting out with if I had to guess, water around 200ppm? I could be wrong here, but what I would do since your reservoir is around 6 gallons is go to the grocery store and buy 3-2.5 gallons of purified water for around $8. Get the RO purified water and you'll start out with 6.5-7.0 PH and 0-20ppm. That way you can get more out of your nutrients and you probably won't even need PH down. Even better, if you live in a house, catch your rain water with a trash can hooked up to your gutters downspout. Hope this helps.

Here is a link that might be useful: How to build a rain collector for $25.

The toxicity level of the three main root types air, water, and medium are directly proportional to their reproduction capacity and inversely proportion to their degree of differentiations. That means more than just the Ph or fertilizer. Oxygen is part of the that matrix too. Ever notice how smaller aeroponic roots are to hydroponics roots. ThatÂs their oxygen toxicity level. And the "directly proportional to their reproduction capacity" is their oxygen matrix. That matrix (proportional) difference then allows you to create environments that cut the growth of hydroponic roots by changing the oxygen toxicity level. But and hereÂs where the rub comes inÂif you change one level you have to change the others as well. That what these Arts & Crafts projects of mine do.
Now stevey do you know how I knew it was the oxygen toxicity level had changed? Because the ph went down. The plant was throwing up all itÂs insides ( brown curling leaves) back into the roots. What happens to anything when it has indigestion. But once it got done with that the roots started to rot which brought the ph high.
You know IÂm really getting into this Pod Squad thing. IÂm making another 5 pods up to hold Swish Chard. Now whoÂs roots are they similar too.

The pH went up. And the water level compared to the roots was exactly the same before as after. I didn't physically remove the plants from the growth medium(hydroton), I just lifted the whole thing out of the water while I dumped the old solution, and poured new solution in.

@UrbanGardenFarmer I have considered making my own rain barrel, but it would be difficult to get the water downstairs and a lot of work. I'd probably just put in a used RO unit with a new filter before I did that.. :P

So I just checked again. The roots that were turning brown now have a plethora of silky white root hairs coming off of them, and the plants are growing strong again.

Thanks for telling me to stop being an idiot and check the pH!

Hey Stevey,

I was curious what type of Hydroponic system are you using and what types of nutrients.

It's a homemade Deep Water Culture system.

I use Dutch Nutrient Formula nutrients.

Sounds like you got the root issue sorted out. I wanted to add another little tip for any one else who might stumble across this thread. PH is a big issue to plant health like the thread creator found out. One big issue to PH swings is the presence of bad bacteria and fungus in high amounts. Odd or bad smells and slime on the walls of the reservoir and on the roots is a sign of this. It is very important to get the natural beneficial bacteria and fungus to colonize before the bad ones. I use General Hydroponic's Subculture B to Inoculate the roots and to get new systems set up on the right track. After the beneficial microbes have taken a firm root in the system the PH will no longer rapidly swing and the smells will go away. During water changes leave a little of the original water in the system to help keep them colonized. If you find your self with bad odors, slime, and root rot add some 3% Hydrogen Peroxide to the system and let it flush for 24 hours then change the water. Let the system run for a couple more days and repeat the process. Do this a few times then flush the system to get rid of the hydrogen peroxide residues that might be present. Then mix up a new water batch with out the hydrogen peroxide and add some Subculture B. Hopefully then the ecosystem within the hydroponics system will become symbiotic to the roots of the plant. Good luck and happy growing!