How to get rid of green-algae developing on tops of perlite substrate?

SU2

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I've been increasingly substituting perlite for DE granules in my substrates and am running into issues with it developing a green algae/slime-mold from being too-moist, it's like once it gets there I just can't get rid of it even if I almost starve/dehydrate the plant, the stuff just won't go away once it's got the tiniest hold (this is surely, at least in-part, a result of a poor container/substrate approach, in that I've got too-many specimen that were cuttings I just stuck in perlite and their containers are so small that they dry-out incredibly quickly, the required waterings - so far as I can judge - cause this, even if I trend towards under-watering)

I've contemplated using hydrogen peroxide in a spray bottle, kind of going by someone here's idea, but cannot find the post where they listed what % they use as their general-purpose cleaner! Any suggestions would be appreciated!! (aside from 're-containerize them', as I'm already on that!)

[edit- not that it matters much, but I swear that perlite fosters this algae far worse than DE ever did, I have enough trees in all-DE substrates that don't have anywhere near the algae problems of the containers w/ perlite! Weird..]
 
I've contemplated using hydrogen peroxide in a spray bottle, kind of going by someone here's idea, but cannot find the post where they listed what % they use as their general-purpose cleaner!
I think it is @0soyoung that talks about it a lot
3% H2O2 that you can get at any grocery/pharmacy.

2 tablespoons of this peroxide in a quart of water.

Good antiseptic --> broad spectrum fungicide + bacteriacide. Safe to use on all common plants.


As for green algae on the soil surface, I don't know it to be a problem. It forms on the surface of my Turface during the winter here (very rainy). It either forms a foundation for moss or it makes a dry crust that does not interfere with drainage/aeration. Further, I don't know that your 'green algae' is my "green algae". And lastly, I don't know what effect, if any, this peroxide solution has on it.
 
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I also like that it can get oxygen into rootbound or solid soil cores...
 
I'm curious if/how the OP solved this issue, as I'm experiencing something similar with about 1/3 of my seedlings. I first thought the green discoloration was just related to the toxic green color of the Miracle-Gro Quick Start fertilizer that I use, but realize this probably isn't the case, otherwise ALL my seedlings would be affected similarly. The substrate is 4:4:1 bark, perlite, peat and gets watered around every 24 hours; the Rootmaker's (photo 2) are in a tent with low-power active ventilation (4" inline) and the white trays are already in the process of being hardened off.

I was already planning to use hydrogen peroxide (diluted to 'normal' strength per the link above) today, and lo and behold, this thread got bumped! I have a lot of Crape seedlings, so feel comfortable (potentially) risking them by doing this, but am curious what causes the problem in the first place. I don't think that I'm over-watering and that airflow is sufficient, but maybe this proves otherwise?
 

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There's a more palatable version for retail on amazon called bio-safe systems disease control. (There's also a mold and mildew control with the same active ingredients & percentages.) Its made by the same company that sells Zerotol (which has the same ingredients but at different percentages). I've only ever used Zerotol ...because I didn't find the other first.
 
Perlite is made out of silicium, and it refracts light in a certain way.
This allows moss, algae and even cyanobacteria to thrive. Since they use very little nutrients, and break down into organic food for the microbiome, I see no reason to get rid of algae. Unless they're blocking water or turning your soil anaerobic.
 
Quick spray with vinegar does the trick for me.
 
When it gets too thick, it curls up when dry and easily peeled off the surface.
 
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