# Algae on my Rockwool Cubes?



## onlyhydro (Feb 18, 2007)

Hey guys, I keep getting algae on the top of my rockwool cubes. Thankfully, I live in a place where i can buy clones at the store, and within a week, about a third of them get a film of either green or black goo on the top. The rest are clean. I keep the humidity at 50%, use gh 3 part, floralicious plus, and root juice. I tried flushing them more often, didn't matter. Other growers say they all get it too and it doesn't hurt the plants but those clones always seem to be lagging behind. Oh, I tried scraping it off but it comes back fast.


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## Vote 2 Legalize Marijuana (Feb 18, 2007)

Hey!
First off, It is normal for you to get algee on your rockwool, Especially when your running high humidity and your rockwool cubes are wet. What causes this is your lighting. To cure this problem, Keep the rockwool covered up. I like to use plastic tubs with lids. Place plants in a plastic tub. Take the lid to the tub and cut out 1" holes for your plants/seedlings to grow thru. By keeping the light off of your cubes algee can't grow. It needs some light to grow. Hope this was a help!!!


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## Al B. Fuct (Feb 18, 2007)

If you're getting algae on your rockwool cubes, they are much too wet. Keep your rockwool damp, never saturated or wet. 

I would strongly advise against putting plants in a tub with a perforated lid, unless you're running an aero system which only mists the roots periodically. If you are running a flood system, a lid with holes for pots will keep the rootzones much wetter than they need to be, encouraging algae, fungus, bacteria, etc. 

If you have lots of algae, it is much wetter than your plants' roots need. This would explain slow growth. The algae won't be able to use up all the food and oxygen your roots need, but the excess water will displace the oxygen from the rockwool cubes, leading to root diseases.

Think damp, not wet!


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## onlyhydro (Feb 19, 2007)

thanks, i'll block the light from the cubes and let them get a bit dryer between waterings


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## potroast (Feb 19, 2007)

I just cut a square piece of panda plastic, and put a slit to a middle hole, and put it over the rockwool cube, white side up. Works fer me.


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## ears (Apr 3, 2019)

1.5% h2o2 and use a spray bottle on a wide spread. 
mix 1oz 35% into 20oz of r.o water and spry the tops of the cube. you are not looking to drench or saturate the cube just 5 or 6 spritz will work it make take a few applications but the added o2 wont hurt. please be careful when doing this because you can over do it and kill everything. MAKE SURE NOT TO SPRAY YOUR LEAFS!


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## JDMase (Apr 3, 2019)

ears said:


> 1.5% h2o2 and use a spray bottle on a wide spread.
> mix 1oz 35% into 20oz of r.o water and spry the tops of the cube. you are not looking to drench or saturate the cube just 5 or 6 spritz will work it make take a few applications but the added o2 wont hurt. please be careful when doing this because you can over do it and kill everything. MAKE SURE NOT TO SPRAY YOUR LEAFS!


This thread was from 2007 man how high are you haha


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## ears (Apr 4, 2019)

JDMase said:


> This thread was from 2007 man how high are you haha


very. it took this long for the right answer! did i win a prize?


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