Dying Roots Problem

by Bob
(Jack and Fish Canada)

I set up a hydroponics like the "My Most Successful Homemade Hydroponics System". However, I went double the length due to the fact that I have plenty of room in the grow area (bad idea I think).

A week into the project and things are not looking to good! I followed your advice in adding additional nutrients: vitamin B1, liquid seaweed, and silica. I noticed that a sludge had formed covering some of the roots as well as what appeared to be mold growing on this brown sludge. I removed all the plants, rinsed off the brown sludge on the roots, and let them sit in a temporary container that was filled with room temp water and 5ml per gallon of Hydrogen Peroxide. I then flushed the hydroponics system with hot water, rinsing off the inside walls to remove all the ugly brown sludge.

After cleaning the hydro system, I replaced the res with only water and 5ml per gallon of Hydrogen Peroxide. Put the plants back into the holes and crossed my fingers! Many of the plant leaves were dying prior to this clean and flush, and as well were not growing as I would expect.

I don't want to give up on this project, however it seems that I am not able to get the water level as high as you described without having leakage. My question is: if the flow rate through the system is too low, will this create a excellent scenario for mold, etc., to start to grow?

Should I drop using the vitamin B1, liquid seaweed, and silica and just stick with the basic nutrients? I am using Bumper Crop A&B and will be switching to Blossom A&B if the plants survive and start to grow.

Answer: Bob- Very sorry to hear about the unfortunate state of affairs! Two things that need to happen here. One- figure out what may have caused such problems in the first place, and Two- try to salvage the current situation. I will start with how to possible save your current crop, but first let me say- the only reason your plants (above ground) are experiencing any damage at all is because your roots (obviously below "ground") have experienced damage. With that in mind, we are going to completely ignore any damage to the plants above and we are going to focus on making and keeping the roots healthy.

Healthy roots cannot be over-fertilized. They cannot be oxygen starved. They cannot be temperature shocked. That's really it, although they should not be exposed to very much light either (darkness helps prevent algae growth in the root zone).

Your feeding program should be stripped down to the very basics- nutrients only (for now). Check them EVERY DAY for the nutrient strength AND the pH. Having either one out of whack can begin killing roots, and once you have dead roots down there you get fungus and bacteria (like fusarium and pythium, which only accelerate the dying of more roots).

Monitor the temperature of the nutrient solution. It needs to stay (ideally) between 65 and 72 degrees. Any warmer, and the water cannot hold as much dissolved oxygen. Oxygen levels in the solution are critical- roots need a little oxygen to keep from drowning! Not only can this start a domino affect by killing roots, but low oxygen creates the perfect environment for anaerobic pathogens (which, in turn, could be the ones killing the roots).

This leads me to the next thing on the checklist....air bubblers. Hopefully, you have at least one or two in your hydroponic system somewhere. They can be in the PVC tubes themselves, or in the nutrient reservoir, but the NEED to be in there. As I said before, a small amount of oxygen in the water is critical to preventing the start of a domino affect.

While keeping these three things in check, you will want to begin to kill off and remove all the bad stuff. To do this, we are going to use the Hydrogen Peroxide. On the bottle, there should be directions for using it in a hydroponic system to add oxygen to the water while plants are actually in the system. Very carefully follow the directions and add the appropriate amount to your nutrient reservoir *with the water pump off*

You want the solution thoroughly mixed so there is no chance the Peroxide itself is going to burn and kill any of the roots (only the slime mold and pathogens hopefully). Once mixed, turn your water pump back on. Over the next couple of weeks, as the bad stuff dies back, it will create a lot of sediment in the system. Much of it will get flushed out into the nutrient reservoir. As it accumulates (if you don't mind using the extra nutrients) you may want to consider dumping it out and changing the nutrient solution.

You can continue to use the Peroxide in this manner for a few weeks, until you begin to get your white roots back and begin to see new growth. However, each time you do a nutrient solution change, the water you use for the next batch of nutrient solution needs to be the right temperature- temperature shock WILL KILL ROOTS. This is why I recommend filling a second reservoir full of water and let it sit out for at least a day before using it in the nutrient change. In this way, you guarantee the temperature of the new solution is the same as the old solution (and both should be in the 65 to 72 degree range).

That just about covers it as far as trying to save the garden. Something started the roots dying. Now you need to go over all of the same points I just mentioned and try to pinpoint where your initial problem most likely got started. It could have been one nutrient change using water that was too cold straight from the tap. I witnessed that exact mistake kill an entire crop of 32 healthy plants almost overnight once- very sad!

Unfortunately, only you know precisely what you did in your grow room over the last several weeks....hopefully you either kept good records or have a good memory....this will take some contemplation. As I said, go over each point I mentioned carefully one by one. I don't believe it has anything to do with the flow rate through the system, but a larger system like you have may need additional air bubblers to keep the oxygen levels up as the water travels through the system.

Too much silica could have done it (adding too much B1 or too much liquid seaweed would not have). Too strong a nutrient solution could have done it. Too little oxygen in the water could have done it. I sure hope you figure this one out Bob, and I sure hope my advice is some help to you on this one! Good Luck!