Why is my rockwool green on top?

This morning i checked on my babies and they are doing good except for slight patches of green on my rockwool. what should i do?

block the light to the top of the rockwool! You can use any black plastic or buy some cube caps. The green stuff is algae. It is not a huge deal but it can start to hurt your plants by blocking the oxygen. It will turn black and nasty. Sometimes if you are growing very short cycles it can be ignored. But blocking the light to the rockwool is a good idea and not that hard to do.

nothing. They will be fine. Some people cover the top of the cubes to keep alge from growing. But it will not harm the plants at all.

hydrogen peroxide!!!!! Mix a lil in a spray bottle and spray affected areas, next time you do a res change add some to your mix and it will keep it from coming back. It is also good for airrating your medium

thanks for the help

Dirtfree said:

hydrogen peroxide!!!!! Mix a lil in a spray bottle and spray affected areas, next time you do a res change add some to your mix and it will keep it from coming back. It is also good for airrating your medium

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And how or at what rate do you dilute it? I tryed the search but i swear its broken.

use 3 percent, undiluted

I put about half a cup in my 15 gal res.

dont use hydrogen peroxide if your using organic nutrients.

I'd pour Hydrogen Peroxide directly onto the cubes to treat the source of the problem, as well as run 1/2 to a full cup of hydrogren peroxide in my reservoir for 1-3 days. After this solution has had a chance to run it's course and help kill off the algae, flush it and replace with a new solution WITHOUT peroxide this time.

The reason you want to do this, is the direct treatment and addition to your res for a few days should take care of the problem, and then covering up the cubes with hydroton or whatever will help prevent any return problems. But the peroxide WILL kill off the majority, if not all, of your beneficial bacteria within the reservoir. The bacterias are necessary for healthy plant growth, nutrient uptake, release of natural aminos & plant hormones, ... Simply use a beneficial bacteria source and replace it in the new res solution when you replace. This will get your ben bacteria stores back up to par and you'll be in the clear and off towards the finish line!

Best of luck

I dont think he is still around considering this thread is a year and a half old, but maybe it will help someone who pulls it up on a search.

I agree with Mazar i Shariff. I'd spray it though and keep an eye on it. The algae isn't too bad for your plant. Its when it grows out of control that you start having to worry about oxygen problems.

Had the same problem with my seedling in a rapid rooter out of the 6 this one had algae. I CAREFULLY took a exacto knife and cut out the top portion that was algae.

Dirtfree said:

I dont think he is still around considering this thread is a year and a half old, but maybe it will help someone who pulls it up on a search.

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It would have helped me when I came across this problem a few weeks back.

Hey Beverhunter, you can also mix hydrogen peroxicide in a spray bottle and shoot it off the top of rockwool.

This thread has resurfaced and is getting attention a year and a half later, gotta love these forums, as long as it is helping people.

i have white mold on the top of my bio sponges, will peroxide work for mold too?

if so, do i not dilute the peroxide when i spray the sponges?

I dont know about white mold. Do you mean powdery mildew?

Yes dilute it with water. 3/4 water to 1/4 peroxicide.

looks like white mold, doesnt look powdery... so 1 tsp of peroxide and 3 water?