Rockwool = root rot?

A friend of mine is curious why he continues to have issues with root rot with his DWC hydroponic setup. He has killed off 6 fem seeds already and now his new crop just began to show leaf drop today and upon closer inspection.. the early stages of root rot with 4 new strains...

Here's what he's running...

950 air pump split across two res 10gal buckets with two 8" air stones each. Using General Hydroponic MaxiGrow line (powder nuts, organic free). pH balanced water between 5.7-6.0 approx 350ppm for plants under 4-5" tall. Good ventilation with two mini fans inside the tent and a small exhaust keeping negative pressure to prevent inbound spores. Temps between 75-80 degrees and humidity maintained between RH 45-55%. His grow area is very clean, wiped down, the floors mopped with diluted bleach and CLR-Mold products.

He's run with and without Hydroguard + Oregonism XL beneficial organisms. With his last attempt (where he killed 6 fem strain seeds) he ran alternating Hydrogen peroxide and deluded bleach. His new setup he's running the recommend concentration of Hydroguard by Botanicare plus a little more than 1/8 tsp of Oregonism XL. In his previous run he used Rapid Start and Thrive Alive liberally, this time he has tried to stay away from them or used in very very small doses (fearing that it could feed root rot / fungi spores).

He's been having to change his res tank way too frequently (every 4-5 days)!

My best guess is that it's the 1" rockwool (which is where the seeds are started and then transplanted into 3" net pots and clay pellets. The 1" rockwool cube is not placed too close to the bottom of the pot or too close to the top -- it's in the center of the 3" net pots and light proof plastic discs are placed at the top of the net pots to aid in preventing light penetration to the root zone or res.

Once root rot is suspected, he immediately breaks everything down, sterilizes everything and cuts away any unhealthy looking roots. However... upon inspection there is black root rot around the bottom of the rockwool cubes that he has to cut away from the cubes... this has happened in both runs (sterile and microbes DWC). Do you that that this is the source of his root rot? He cannot image where else it would be coming from. I'm thinking that his water level is too high. I've read all different opinions on water level's. So for his first run he kept water levels 1/2" above the bottom of net pots. This run he is running between just the bottom of his pot where it's barely touching or barely below. Upon inspection other holes in the DWC bucket that are not being used but are filled with clay pellets and covered, when he looks at them they are all moist. Provided that he's running two highly aerated airstones, perhaps he needs to keep the water levels even lower to prevent too much moisture in the root zone and therefore surrounding the rockwell cubes?

He's very interested in some feedback as he's very frustrated
Thank you!!!!!

I stopped using rockwool after losing my last two grows. The rockwool didn't cause it but I believe it was infected. Not only that but it's very hard not to overwater it no matter the water level in my personal experience.

If you can only get clones in rockwool you could build an aerocloner and remove the rockwool and start over. Will cost you a couple of weeks but atleast you won't have rockwool issues.

Sometimes depending on where you live you can but cuttings off people instead of rooted clones.

I've always used Grodan delta6.5 blocks in my 6" netlids. ZERO issues with root rot for the past 3 years-no chillers, just using GFF as an inoculant. The only issues I've ever had was when I ran the water level to high and it allowed the cube to wick up solution. No rot but I did start to see some fungus gnats.

My friend has ordered more fem seeds just in case any strains are lost or too far gone... but this is super frustrating (and very expensive). It's not just the time but the expense (because who wants to use cheap seeds/strains)? My friend does not have access to clones -- because seeds are his only option he is attempting to geno/pheno hunt the best strains down to 6 for one DWC bucket and have a separate space for mothers for a perpetual grow under 1 x 96 watt T5 2' grow light [which he's currently using two of with two separate buckets]. Everything goes great until the plants are about 2-3" tall with 2nd or 3rd node / leaf set... then growth slows, followed by leaf droop, eventually every variety of nut deficiency is observed... grrr....

... so it's the water level? I'm assuming if the clay pellets always stay wet due to water level and aeration from bubbles that the water is too high as the rock wool is going to be constantly over saturated eventually leading to root rot? No amount of beneficial microbes can prevent rock wool from rotting if it's constantly soaked I assume?

What water level do you use to avoid disease in DWC?

Just start the seed in a paper towel and then move it straight to your system. I've not done this but I have seen it done and with great success. You'd have to find the info for the process but it seemed pretty simple to me.

Thank you for those who have replied so far. The info is appreciated. A friend of mine has some photo's...

He has an aerocloner as you can see not in use. Well he has a couple lonely tents too wanting to be filled...

Take a look at how the clay pellets are still too moist in his DWC... he's gone from a water line 1" below to now 2" below (he measured!).

You can see the front DWC bucket that it shows beginning signs of leaf droop -- he removed all the yucky black rockwool and unhealthy root segments earlier today and soaked in hydrogen peroxide 3% before soaking in hydroguard at 3x strength. Then he put them back in their clean DWC (changed just yesterday) The DWC bucket in the rear has only one strain left out of six which finally appears to be recovering after several weeks.

In reference to the photo's... he even suspects root rot starting with a new seedling in rockwool (which he's never had before at that earlier of a stage -- he introduced beneficial microbes to it and now wonders if it wasn't a bad idea). You can also see some of his casualties of war (... the pythium war that is) RIP Sensi skunk, LA Sage CBD, Pineapple chunk, and Early widow... he hopes not to have to bury anymore siblings in the family plot

Update... my friend reports no change. He's unsure if these will survive or not (considering that he caught it early). He's so exhausted by root rot...

@ shawnery -- my friend like's your thought. If rockwool is the problem and common denominator... then eliminate it! He did some added research on the forums and found that Rapid rooter plugs (made of encased peat moss) have had success and can be easily cut away before transplant into DWC. Much easier than rockwool of course. I wouldn't think that peat moss and DWC would be a great combination anyways.

Thoughts?

jjng5 said:

I wouldn't think that peat moss and DWC would be a great combination anyways.

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read my reply in the other thread. rapid rooters are way better and have no problems in dwc.

Rky is the man!

shawnery said:

Rky is the man!

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even a blind squirrel can find a nut. lol.

Thank you Rky -- my friend took your advice! They're on the way!

Any advice on treatment for the injured girls? My friend might tear down the system again tonight to cut away any remaining rockwool and give another bath in h202 before putting back into microbe rich DWC. I'm sure after the h2o2 soak that it will kill many microbes in the DWC tubs but if I continue to add a little every day they should stabilize I'd think... what do you think?

jjng5 said:

Thank you Rky -- my friend took your advice! They're on the way!

Any advice on treatment for the injured girls? My friend might tear down the system again tonight to cut away any remaining rockwool and give another bath in h202 before putting back into microbe rich DWC. I'm sure after the h2o2 soak that it will kill many microbes in the DWC tubs but if I continue to add a little every day they should stabilize I'd think... what do you think?

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just got to look at all those pics.

first, pic that ends in 106: is that what they look like now? they look in very sad shape. i would take a razor blade and try to cut them out of the rockwool totally. be real careful with the roots and damage the least amount possible.

the other pic looks like the lights are way too close to the plants. they look like some htg supply lamps i used to have. i'd give them at least 24 to 36 inches away from those small plants. i think they are getting too much light too.

rkymtnman said:

just got to look at all those pics.

first, pic that ends in 106: is that what they look like now? they look in very sad shape. i would take a razor blade and try to cut them out of the rockwool totally. be real careful with the roots and damage the least amount possible.

the other pic looks like the lights are way too close to the plants. they look like some htg supply lamps i used to have. i'd give them at least 24 to 36 inches away from those small plants. i think they are getting too much light too.

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No pic ending in # 106 are some of the fallen causalities of war (the pythlium war). My friends fearful that the strains shown in pic ending in # 344, might follow . He's hoping to save them if he's able... so frustrating... strains lost, time lost, needless waste... He's still going to start some new ones and keep all of these together in the same DWC tub/chamber and start new ones without rockwool in another, just in case these start to slide down hill, he doesn't want to spread disease. He wants to try and preserve these strains...

Regarding the lighting -- he has them under a 2 foot T5 fixture (4 bulbs x 24w each). You still think that that's too much and he should raise them higher? He's keeping them about 2" above the tops.

He's going to take your advice and break everything down tonight to strip any remaining rockwool, rinse the roots again, and soak in h2o2. Grrr.... Let me know if you can think of anything else. Thank you!

jjng5 said:

nding in # 344,

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those don't look bad at all. do you have a pic of what the roots look like in 344?

one thing i would do would be to remove those white things that stick up from the net pot. the white covers are a great idea but they need to be flat on the top of the tote to block out all light.

the other thing i would think about doing is to buy some of the krylon spray paint for plastic and paint the whole tote black. that grey is decent but it does let a fair amoutn of light come thru. definitely not as good as black totes.

make sure the hydroton gets a good soaking in h2o2 too.
the t5's are fine. it looked like they were under HID lights in one pic. my mistake.

what is he using for root rot prevention?

Black and then white. Black for light protection and white for light reflection and lack of heat absorbtion.

Should have done it on my lids but only did black.

shawnery said:

Black and then white. Black for light protection and white for light reflection and lack of heat absorbtion.

Should have done it on my lids but only did black.

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good point. white would keep it cooler for sure.

Thanks Rykman -- my friend put three coats of white Krylon plastic spray paint on the top like you suggested.

Rykman... I'm convinced... rockwool is the enemy. Even after digging root rot out... take a look...

Pay close attention to all the black cruddy egg spores hidden like a cancer! Just when you think you got it, it's deeper. Take a look at the bubbles gushing off the roots (even the white ones)...

image #3625 ... look at the floaters. My friend spent hours with tweezers... that stuff sticks on like slimy goo that holds on and won't let go to the smallest deepest root segments.

Those are pieces of rock your finding not eggs or bugs, perfectly normal for rockwool.

I would recommend he monitor water temps and ensure the containers do not leak light. This is what will cause root rot 99% of the time. Root rot loves warm water.

Your water level should be below the net pot. 1-2 inches until roots drop and than it can be lowered to whatever you prefer.

Are the air pumps being run 24/7? Def keep the air pumping 24/7

What are the temps with lights off/what is the light schedule, and what are the water temps lights on and off?

He did away with the rock wool and now has powdery mildew in the aerocloner (which is rockwool free)!!! ...

White spores are forming on the edges of the foam. He opened the cloning bucket and the water was hazy and the sides of the bucket had what looked like spores. See the photo's attached.

He changed the water, cut off any dead leaves, soaked the foam inserts in diluted bleach water, sprayed the plants with neem oil along with the surfaces of everything (foam/lid), and turned the water pump spray power down to 50%. And *THEN* 24 hours later... white spores are forming again on the rubber foam inserts. He notices that there is moister between the cracks of the foam, but water is not leaking out... take a look at the photo's...

The water is 67.5 F and the cloner bucket lid has three coats of krylon white spray paint. I cannot see it being temp/light unless I'm missing something. Hydroponics is becoming so frustrating... grrr... he switched to the aero-cloner to get away from root rot from the DWC and now he's battling white mildew!

Any thoughts? Thank you for your help!!! Ahh...