Is this root rot?

[sylvestris]

Hi!

I've recently moved my chilies from my cloner DWC to my home made full size DWC. I'm using Canna Aqua Vega nutes and aprox pH 6.0 and 200 w cfl blue.

The problem: The roots on the plants have turned slightly brown/red with a little slippery surface on them. Have they been struck by root rot? :S

So far I've started adding h2o2 (liquid oxygen) according to instructions and just recently i've started using frozen water bottles to chill my nute solution.

Is there any way of telling if it's root rot, algae or "normal" perhaps discoloration from nutes. My plants doesn't really seem affected by it. My chilies have actually started budding at only 15 cm height. Also they've got some "dry patches" on the top leaves.

One thing i noted though, was that when moving the plants they stopped developing the roots they came with from the cloner and started sprouting new roots, a bit sturdier roots. Almost like a hedgehog (make sense?)

Here's some pics:
http://dl.dropbox.com/u/16543382/DSC00037.jpg
http://dl.dropbox.com/u/16543382/DSC00038.jpg
http://dl.dropbox.com/u/16543382/DSC00032.jpg
http://dl.dropbox.com/u/16543382/DSC00033.jpg

[GpsFrontier]

sylvestris
1. You mentioned that you started to use ice to cool the nutrient solution, what is the temperature of your nutrient solution (before and after)?
2. How long have they been that system and between nutrient changes?
3. Is the nutrient solution cloudy?
4. when did you first notice any browning.
5. Do you feel the same slippery surface on anything else in the system (side of container, baskets, tubes etc.).
6. is the browning only on the roots that are submerged in the nutrient solution?


I see the new white roots growing out, and that's typical when warm nutrient temps cool down again. Tinting from the nuts themselves is normal and possible, however I don't usually see it that dark with roots that young. But I have never used those nutes either. Also I see some bubbles in the water so I assume you have air stones in it, however I cant tell if they are getting enough. Most of the white roots look like they are coming out of the sides of the baskets, so I wonder if they only turn brown when they become submerged.

[sylvestris]

Thanks for your reply!

1. The solution is about 17 degrees C without ice and around 14-15 with ice.
2. The plants have "lived" in that solution for roughly 10 days, i started them in a small cloner type DWC. I have not changed nutes yet, only filled the system up with water.
3. The nutrient solution is not cloudy
4. The browning started appearing a few days after i moved them to the bigger system. It also feels like they slowed down their growth rate, at least the chilies, but that might be cus they started budding (ive pinched those away now though)
5. That slippery surface is gone now, i can't find it on anything in the system
6.The browning is only on the roots submerged in the solution

Let me get this right, you say that new roots are typical when the roots have grown in a warm solution and then cools down? That makes sense Because my cloner system only held about a litre of water and so it was always luke warm to the touch. Probably well above 22 degrees celcius. Maybe the roots reacted to the lowered temperature? My DWC was at about 10 degrees celcius when i started it, the water was almost freezing my hands when i dipped them.



I'm using a 150 mm air stone, its a pretty big one, almost covers the bottom of the dwc.

[GpsFrontier]

sylvestris
Ya, if the water was too warm that would damage the roots, then when it cools down the plant tries to generate new roots. But 17 degrees C is not too warm, in fact 20 degrees C (68 F) is better. Cold water wont cause the roots to brown, but it does cause stunted growth. The optimum water temp is between 20 C and 22 C. If the nutrient solution is only 10 days old and not cloudy, and you say you don't feel anything slimy (slippery), and the plants look otherwise healthy, I only have 2 likely suspects. First I forgot to ask if the nutrient solution has a bad smell, but if it isn't cloudy I don't think it would.


So I would suspect that it's probably due to either tinting from the nutrients themselves (especially if they are mixed on the strong side), and/or the submerged roots may not be getting enough air bubbles, and may be suffocating. But as long as the plants are looking fine and you are happy with the air bubbles, I wouldn't worry about anything at this point. Although I would raise the nutrient temp to 20-22 C.

[sylvestris]

I just changed the nute solution, fingers crossed. I have some questions though.

-What does root rot smell like? My roots smell a bit earthy, almost like lettuce or cigarette smoke (strange i know)

-How big air pump do i need to supply a container of 15 litres (about 4 gallons) with air?

- At roughly what distance should the water level be in relation to the bottom part of the net pots? I read somewhere that a fair distance is good to provide some oxygen to the roots and thus prevent root rot.

Thanks for your answers Gpsfrontier

[GpsFrontier]

Hello sylvestris,
Sorry I somehow missed your post. The roots (and/or nutrient solution) should not smell bad. If they do, that could be an indication that something is growing in your system that you don't want there (fungus bacteria etc.). For 4 gallons of water (nutrient solution) you could use just about the smallest air pump available. Generally any fish tank air pump will say how many gallons it works for, I use that as a guideline. But more air bubbles never hurts anything, so I always try to get the biggest I have money for. And plants that don't like wet feet will benefit even more from all the air bubbles they can get in a water culture system.

As for the distance from the bottom of the net pots, that's something that varies from one person to another, plant to plant, and setup to setup. I like to make it adjustable and change it as the plants grow. Just touching the bottom of the baskets when they are small so the growing medium can wick up moisture. Then drop the water level down as the roots grow down into the solution. But not so far that the roots cant wick up enough moisture to keep the growing medium in the baskets moist. The idea is to keep the exposed roots moist (as well as what's in the baskets), but not saturated. If the growing medium becomes too saturated that can even lead to stem rot. If they dry out then the plants suffer, but some plants tolerate wet feet better than others. I would say just play around with the water level and see what works best for you, and in your situation. Hope that helps somewhat, and sorry it's so late.

[sylvestris]

Hi!

No worries! I'm just glad someone replies

I probably was worrying too much, it's still growing fine, and the plants look healthy (apart from the ones i accidently put too close to the CFL, which are slightly burned).

The water level is now about an inch from the pots and it seems to be working. However it seems the roots like growing in mid air, more than in the water. Above water they are white and fat and below water they are more "skinny".

My biggest concern now is that my chili plants are just producing buds and has virtually stopped growing. Anyways... thanks for the reply

[GpsFrontier]

The chili plants not growing that much now probably has nothing to do with them budding, but rather the amount of light they are getting from the florescent lighting. Even though they do expend a lot of energy to grow the produce. But they are continuously fruiting plants and are able to do both at the same time.

Florescent lights don't work well with tall plants because the farther away the leaves are from them the light, the light intensity drops significantly (especially in comparison to metal halide and high pressure sodium lighting). A few inches can make a huge difference in that regard. So even though the tops are close enough to the lights, the lower portion of the plants are likely not getting sufficient light. That would cause the growth to slow down and probably even stop, because they are not getting the light they need for photosynthesis and growth.

[sylvestris]

The strange thing is that they are only about 20 cm tall at the moment so they should keep growing.

Gonna get my Aeroponic system up soon. Will be interesting to compare growth.

Thanks again gps