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Mould on rockwool cube

Discussion in 'Marijuana Plant Problems' started by GreenGro, Jul 17, 2007.


    GreenGro Well-Known Member


    I have a bit of mould on top of my rockwool cubes, is this a worry and what can I do about it please?

    *Edit I just pulled 2 pots out and the roots are going slightly brown and mouldy looking, so I guess this is a problem - will adding H202 save the day now? or should I get some clones when I can?


    GreenGro Well-Known Member

    Can't anybody help? I really don't know if these plants are savable now or if I should rape them for clones and throw them out and disenfect everything.

    Any help gratefully received, a couple more hours and I gonna have to do something, right or wrong. Thanks

    GreenGro Well-Known Member


    I know I'm answering myself in this thread but I'm hoping someone will chime in in the end.

    I have just dumped my tank and it is full of like bacteria like big slimey bits, absolutely full of them. Anyway I have cleaned everything down with bleach and water filled a new tank and what have you but I'm worried that the bit of brown on the roots is going to cause this shit in the tank again.

    Firstly I'm not sure what it is or whats causing it, secondly I would like to know what will fix it. I have some H2o2 on order but its gonna take a few days to get here, will this fix it or if not what will.

    Thanks. Please help..beg...beg...

    Jazzman Well-Known Member

    What's up Green - So sorry nobody's helping you out yet man... Please don't get your hopes up, though - I'm just a lame ass newb. While you're waiting for some serious advice, however: Get some H202 in your res NOW! What the heck are you waiting for bud? I'm assuming you've ordered some "real" H202, but in the meantime, just grab some 3% from a local store! I'm using about a 1/2 ounce per gal. at each res change, and replacing 25% daily. My plants seem to love it. That amount is for relatively healthy plants though, and a clean res. Do a search here, and I'm sure you'll find some recommendations for active root rot and algae.
    Speaking of algae - is your res completely light proof? Don't assume, like my dumb ass did. Also, the brown on your roots, even with my limited experience, sounds like root rot. Make sure your res is well aerated; add more airstones, or a better air pump. AND make sure your tank temp is in a good range. I believe they say, especially with any hint of root disease and "crap in your water", to try to keep the res at a nice LOW temp... 68 deg, at least until you resolve your problems. That will still allow for healthy growth, but won't be warm enough for anything that's NOT supposed to be there to grow..!
    Good luck man, hope you work it out! And don't be discouraged, bro, SOMEONE will help you - just be patient! The people here are very cool, and very helpful. One thing, though: you need to give some more specifics on your setup if you expect people to really help you.
    OH - Forgot about the mold! Wow, I'm so sorry dude! Are you sure it's mold, and not just mineral salt residue? I had the same problem, with white stuff all over my rockwool. Got lucky, I suppose, as it wasn't mold. What's your humidity been like? Your room, and setup clean and relatively sterile? Again, post more specifics, and someone WILL help you figure it out. PEACE:peace:

    GreenGro Well-Known Member

    Thanks Jazzman

    The H202 is coming tomorrow, when I asked about before it didn't seem like everybody used it so I didn't use it.

    When you say grab some 3%, 3% what?

    The res is not totally covered on top by the tray (ebb flood) but not much light gets in, I thought this was ok, its mostly covered.

    I think it was mould on the cube, it was white but when I rubbed it it went black.

    I do need to start monitoring the temperature of the res, this is something I know I ought to be doing but haven't got around to it, I will pull my finger out!

    Thanks for the help, I will just have to try to save them. Can I spray the rockwool cubes with H202 to kill the mould and spray the roots to kill the mould there?

    Jazzman Well-Known Member

    GreenGro - What's up bro. When I said "3%", I was just referring to the weak H202 that they sell at your local stores - supermarket, drugstore, walmart, etc. The longer you wait, the worse your problems are gonna get man.
    Sorry Green - I don't know much about Ebb and Flow systems. However, ANY light hitting your water is going to cause algae to grow. Light hitting your roots is even worse.
    H202 is not going to help kill the mold. I think mogie posted some great info on killing mold; do a search man. If I remember correctly, you can spray alkaline water on the rockwool cubes, and... I think baking soda also works. Once it's there, though, I have no clue how hard it is to truly get rid of it. And, as far as I know, taking clones from a plant with mold problems is NOT a good idea. Try to find the post on dealing with mold, and check out some of the more serious products they sell to kill it.
    Also, search for H202 as well. Just getting it in your water ASAP will help with your some of your root problems, and the nasty water/algae. Block that light man! Also, I think there are directions for an h202 "root soak" on here somewhere. You might want to post in the Hydro section too, bro. You need more help from someone experienced. In the meantime, READ man! Search! There's a ton of info on this site, you just have to be patient, and find it... Good luck man, keep me posted! Peace:peace:

    nongreenthumb Well-Known Member

    I'm guessing that there is green showing on the rockwool?

    If so I can help you

    laserbrn Well-Known Member

    Definitely want to use Hygrozyme or some H202 to stop bacteria production and I always make sure that I'm running a good stir pump in the res. Some green on your rockwool cubes is normal. I've never had any problems caused by the green on the rockwool cubes. It's not mold, it's algae and it happens when light hits moist rockwool cubes.

    As a note: I changed my res. on Sat. and DID NOT add hygrozyme or H202 because I'm out and I'm going to have to flush it again tomorrow. I need to run to the local hydro store to get some nutes and hygrozyme as I just wasted what I wanted to be the last of my nutes.

    Majestic12 Member

    Hello all, I am on my second grow using a EBB & Flow Megagarden with 8xT8's. I too have green residue on my rockwool cubes, and it smells like the algae from a fish tank. Some cubes are more green than others, but I'm just confirming this would not hurt the plants? I was going to start cutting squares of mylar with a slit in them to cover each pot to increase general light effiency, but I was hoping this would get rid of any algea as well.

    laserbrn Well-Known Member

    Covering the cubes is best. I don't run with the "it's okay" mentality anymore, funny what a couple of years will do for you. covering the cubes won't get rid of the algae per say, but it will inhibit the growth. Too much alagea means feeding your nutrirents to the algae and it can make things a little bit unpredictable. Overall it's not the end of the world and it probably won't do harm, but seriously algae infested cubes are nasty and covering them is a good solution.
    skoobie dew

    skoobie dew Well-Known Member

    If the algae gets bad it will inhibit the capillary action of the rockwool and prevent proper drainage. If it's not to bad then use some black and white poly http://www.bghydro.com/BGH/itemdesc.asp?ic=HLMYBWP/025&eq=&Tp=
    to block light from getting to the top of your rockwool cubes. It needs to be on loosely, so that it doesn't prevent air flow to the where the trunk of your plant meets the rockwool.
    Also anything that is moist and exposed to light and air will develop algae. Algae will eat your nutes and cause ph fluctuation if it gets out of control imho.


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