Ebb&Flow_Rockwool_root rot

Dear gardeners,

I am new to the hydroponics and I am very much struggling since the beginning as my plants does not seems to do very well. Growing in the room of 17 x 10 x 7ft, Ebb&flow system, 4 trays, rockwool cubes with clones planted into rockwool slabs, 600W HPS hanging around 25inch above plants, split AC running 24/7, exhausts running 15min on/15 off, intake fan running every 30min, approx. temp./RH when lights on 79-85F/35-45%, approx. temp./RH when lights off 68-72F/50-60%.

I got the clones 3 weeks ago, everything seemed fined until I placed them into 5.6PH/1.2EC pre-flooded rockwool slabs 2 weeks ago. I have probably made a mistake with too little drainage holes and I let the roots sit in the moist/water for 4 days when I realized something is going wrong so I made cuts basically along the whole slabs. However, that was too late as the problem manifested itself on the leaves which started to twist, turn yellow and eventually turn brown and wither. By the time I am writing it I had to "defoliate" almost all of the big leaves as they were slowly dying. The new ones are occurring but very slowly. Everyday I have to pick off a handful of leaves that would otherwise fall off. I was told it is caused by a root rot but when I opened the slab from the bottom, roots seemed fine and thriving. For the last week I am flooding every second day with RO+Hydro A from Atami sitting at 5.7PH/1.4EC.

I am going to be very thankful if anyone can advice me how the get the girls better. Thank you

How many 600’s?

Never grew in the block but definitely have done 1000’s of those 4 inch cubes smack dab on my tables flood and draining every 6 hours half way up the cube.

Herb & Suds said:

How many 600’s?

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8 of them

smokey0418 said:

Never grew in the block but definitely have done 1000’s of those 4 inch cubes smack dab on my tables flood and draining every 6 hours half way up the cube.

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so should I flood once every day instead if every second day? Slabs seemed too heavy the other day after the flood to water them again imo

Not related to your roots but looks like bug activity.

I’m reminded why I hate rockwool

bbaxxx said:

so should I flood once every day instead if every second day? Slabs seemed too heavy the other day after the flood to water them again imo

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No no, you will have to figure that one out.

Your working with a sponge.

Are you using the B'cuzz Hydro from Atami? You said you were flooding with RO water and Hydro A from Atami. Did you just forget to say you were using part B? You're supposed to use parts A and B together. Not everything is in one bottle. There's no phosphorus in part A. Phosphorus is a macronutrient and essential for plant growth.

xtsho said:

Are you using the B'cuzz Hydro from Atami? You said you were flooding with RO water and Hydro A from Atami. Did you just forget to say you were using part B? You're supposed to use parts A and B together. Not everything is in one bottle. There's no phosphorus in part A. Phosphorus is a macronutrient and essential for plant growth.

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Well, they F my order as I received two A’s. Now I am waiting for the B but I was told by the guy from the grow shop that the B will be needed when I flip to 12/12h which I havent done yet since Im waiting for the girls to bounce back at least a bit. On the other side, he could just told me that without having any knowledge about it which I would not be surprised tho

bbaxxx said:

Well, they F my order as I received two A’s. Now I am waiting for the B but I was told by the guy from the grow shop that the B will be needed when I flip to 12/12h which I havent done yet since Im waiting for the girls to bounce back at least a bit. On the other side, he could just told me that without having any knowledge about it which I would not be surprised tho

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The guy at the grow shop doesn't know what he's talking about. Part A and Part B need to be used together. As I said, there is no phosphorus in Part A. I looked up those nutrients. You're missing one of the 3 macronutrients if you're only using Part A.


APPLICATION
Because certain nutrients in the solution chemically react with each other in high concentrations, the nutrients come in two separate bottles, A and B. The A and B concentrates may only be mixed with each other in combination with water.

DOSAGE
1 – 3 ml A and 1 – 3 ml B per litre of water.

In the beginning youre far better of with drippers than flooding a slab, its ok when they're big but when they are little, a flood cycle water logs the Rockwool , even if its 1/2 inch high it will suck it up like a sponge, soak the slab let it drain place cutting on top with a dripper near and run it a minute once a day, once they get big they cannot be over-watered, best you can do now is don't water them and let them dry out, the rot may get worse before better but you have a bog now and no additive will get you out of trouble they need air at the roots, if they perk up and get turgid then start the 1 min feed cycles, generally when something like this happens it will cost you 2wks in time if you make the right moves and fix the problem.

If you have anything close to poor ventilation and air exchange then Rockwool will never work for you, it will be sudden death when you think things are going ok, you may get a crop out when the outside climate is suitable but any demand like in summer placed on them and they crash because of the water holding and poor root development not being able to breathe.