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Algae, Mold / Slime Mold and Sand

gill_za

Never Knows Best
I just dumped a pot because it got covered with a mix of mold and algae and some other green c@#&. It looked like this but 100x worse, with dark green dry patches and fluffy white mold everywhere:

20110404003.jpg


20110404002.jpg


It was one of my first pots and I did not wash and microwave the peat : perlite mix that it contained (now I try to wash and then microwave everything and avoid perlite whenever possible) So after about a month, the surface started to become green. First I tried to fight it with peroxide but it would always grow back. Neem oil ( extracts at 1%) did not help. And few days ago it started to smell..

So I was wondering if this happens again would it help to cover the soil with a layer (5mm) of coarse sand to suffocate the algae/fungus/and whatever else grows there.
I currently have Butterwort, VFT's, Sarracenia, and Droseras will these plants tolerate a top layer of sand on their soil?
 
Cooking your peat moss in the microwave oven causes it to start breaking down faster. This leads to increased nutrients in your medium. Try sterilizing with a 10% bleach solution and/or rinse everything thoroughly.

See Tamlin's article:
http://www.terraforums.com/forums/showthread.php?t=99738
 
That is some nasty looking stuff. Never saw this one before, hope I never do.
 
Cooking your peat moss in the microwave oven causes it to start breaking down faster. This leads to increased nutrients in your medium. Try sterilizing with a 10% bleach solution and/or rinse everything thoroughly.

See Tamlin's article:
http://www.terraforums.com/forums/showthread.php?t=99738

I heat a pot in microwave for 3 to 5 minutes. When the mix is wet all it does is raise the temperature. The bottleneck here is moisture in the peat preventing the temperature ever going over 100C. So if the peat is wet microwaving it for short time will not start decomposing it I believe. I additionally flush it with copious amount of DI water after microwaving (to cool down).

P.S. What about my question ? :)
 
heat and moisture combination speed up media breakdown. i would dry nuke it or mist lightly if you must have it on the moist side. for what its worth, i rinse/let media sit in water for a few days before using and just scoop it out and squeeze out excess water when i need it (peat floats) and have never had much of an issue with algae.
 
I have read in other threads about sterilizing peat with 10% bleach solution as well. Are we talking about a common laundry bleach (clorox) diluted to 10% or is it a pure bleach (no additives).

Since the mechanism of sterilization is essentially oxidation could the same effect be achieved using Peroxide solution? I believe it would be better since there would be no need to get rid of sodium and chloride ions from the media, peroxide breaks down into water and oxygen only.

Which brings me to another point. Sterilizing media via microwaving, bleaching or using peroxide is essentially oxidation of media. Microwaving might just additionally result in marginal anaerobic oxidation. Out of all three peroxide and microwave seem to be the cleanest ways of doing it.

After those two first pots when I used as_is_media (no washing no sterilizing) I made it a habit to thoroughly wash the media in the big bucket several times with tap water (3 - 4 times with 5 gallons) and collecting peat via two sets of sieves (mesh 40 and 60). I then do the same using distilled water.
Remaining water is then squeezed out and peat is mixed with sand. Sand is washed separately following the same procedure but not using sieves. Mixed media is transferred into pots (sterilized by spraying 3% peroxide all over them and letting dry out), followed by 3 - 5 minutes of microwave on High. Media is then flushed with cold distilled water.

I have noticed very little algae growth in the media handled this way when compared to my first two attempts. And whatever green I find in there gets quickly zapped with peroxide. But I am now a bit paranoid since I transferred some of the plants from old pots into new ones and had some algae/mold clinging to the leaves. I am afraid I have contaminated the clean pots. Thus I was wondering if a layer of sand might help suffocate mold and algae and keep fungus gnats at bay.

P.S. I did read the article mentioned previously during my lurking times. This is where I got the procedure outlined above.
 
If you want to go against the advice of people like flytraplady5 who have potted up thousands of plants go ahead. Experience trumps common sense.

If you are heating the peat moss you are causing the water within to expand which can burst the cell walls. It is the spongey cellular structure of peat moss that makes it retain up to 20 times its own weight in water. Oxidants are less likely to cause massive damage.

The minimum amount of time to sterilize liquids and dry goods in an autoclave is 15 minutes (essentially pressure cooking). For waste liquids and solids the minimum is 45 minutes. 5 minutes in the microwave isn't likely to ensure biological inactivity.

At best you are pasteurizing your media which just slows down microbial activity, not eliminating it. And if your peat moss starts breaking down it's going to provide a richer medium for algae etc as well as providing an unfriendly environment for your plants.

A sand mulch might prevent surface growth but do little for fungus or mold deeper down in the medium. Besides I've seen algae growing on surface sand.
 
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If you want to go against the advice of people like flytraplady5 who have potted up thousands of plants go ahead. Experience trumps common sense.

If you are heating the peat moss you are causing the water to expand which can burst the cell walls. It is the cellular structure of peat moss that makes it retain up to 20 times its own weight in water. Oxidants are less likely to cause massive damage.

The minimum amount of time to sterilize liquids and dry goods in an autoclave is 15 minutes (essentially pressure cooking). For waste liquids and solids the minimum is 45 minutes. 5 minutes in the microwave isn't likely to ensure biological inactivity.

At best you are pasteurizing your media which just slows down microbial activity, not eliminating it. And if your peat moss starts breaking down it's going to provide a richer medium for algae etc as well as providing an unfriendly environment for your plants.

A sand mulch might prevent surface growth but do little for fungus or mold deeper down in the medium. Besides I've seen algae growing on surface sand.

OK. So the advice is not to microwave/peroxide/bleach, but just wash thoroughly?
 
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