Algae and Bleach!

[empiref]

Hello all,

I have searched extensively on this forum for Algae solutions, and I wanted to get some answers for my questions.
So if you please bare with me, thanks.

I have read that bleach (household bleach) can be used to get rid of algae buildup in S/H clear containers, mine are starting to get green at the bottom rapidly. The pots are big 19 cm diameter and 26 cm height. Aesthetically, it's looking ugly.

Unfortunately, where I live in Lebanon, Physan 20 is not available, and to buy it online and ship it here, it's gonna cost me lots of money.

• What is the recommended amount of household bleach to water that can be used to get rid of the algae buildup, and in the same time not harm the orchids (phals). In metric system please, for example, one tablespoon of bleach per one liter of water?
• Another question is, when i pour the the bleach/water into the medium, should I close the drainage holes and leave the medium to soak? and for how long?
• After soaking the medium, should I empty the reservoir in the bottom of the pot from the bleach/water solution and replenish it with normal water?
• How often should the bleach/water solution be used, every month for example? as a preventative measure and as a treatment for the existing algae problem.

Thank you all for your patience and help.

[catasetum-ian]

Hello all,

I have searched extensively on this forum for Algae solutions, and I wanted to get some answers for my questions.
So if you please bare with me, thanks.

I have read that bleach (household bleach) can be used to get rid of algae buildup in S/H clear containers, mine are starting to get green at the bottom rapidly. The pots are big 19 cm diameter and 26 cm height. Aesthetically, it's looking ugly.

Unfortunately, where I live in Lebanon, Physan 20 is not available, and to buy it online and ship it here, it's gonna cost me lots of money.

• What is the recommended amount of household bleach to water that can be used to get rid of the algae buildup, and in the same time not harm the orchids (phals). In metric system please, for example, one tablespoon of bleach per one liter of water?
• Another question is, when i pour the the bleach/water into the medium, should I close the drainage holes and leave the medium to soak? and for how long?
• After soaking the medium, should I empty the reservoir in the bottom of the pot from the bleach/water solution and replenish it with normal water?
• How often should the bleach/water solution be used, every month for example? as a preventative measure and as a treatment for the existing algae problem.

Thank you all for your patience and help.

Hi Johnny,
i was initially taught to use 1:9 dilution of commercial household bleach. after several tries, i modified it to 1:12 dilution.
i usually just sprayed on top of media to get rid of the mold/algae.
leave it there for about 10 minutes and after that RINSE THOROUGHLY (make sure you rinse it enough). that would do the trick.
some orchids dun handle these bleach bath that well from my own observation, bulbos and very young catasetums that just send out their roots. phalenopsis had no problem with this. i had not tried on other orchid genera yet.

[zainal abidin]

Hi Johnny
I never practice use bleach to remove algae, I don’t like it so corrosive and hate the Chlorine smell too ,very dangerous to our skin respiratory tract and maybe the plants.
Come to basic:
Usually algae may appear when the medium is too wet and no time to dry out.
When use to much organic fertilizer.
To me where I live in Equator:
I will avoid using a media that can retain too much water.
Limit the use of organic fertilizer at least twice a month.
Use a basket or clay pot.
So far it works for me.

[Germinatorman]

I would get online and search hydroponics blogs and sites, especially resellers. There must be this same issue in the hydroponics industry. I have the same issue but I just live with it. Mix water and sunlight and something to grow on, you are going to have algae.
Don

[Brutal_Dreamer]

You could also repot into non-clear semi-hydro containers. That should eliminate the algae problem without chemicals.

cheers,
BD

[Halloamey]

I do not recommend the use bleach at all if the orchid is going to be exposed to bleach as well. If it is for empty pots then 1:9 bleach is good to disinfect and kill the algae. For Sh I recommend you use hydrogen peroxide 3%. Just pour it over the roots and let it drain. Also regular strong flushing with freshwater without any fertilizers should also get rid of the algae.

[pavel]

I agree with Amey. A 1:9 ratio is what I use to sterilize plastic pots. I really would expect this to be far too strong of a concentration for the orchid to be exposed to.

On a different but related note ... a friend of mine, now deceased, grew most of his plants in s/h with great success. He was, at first, worried about the algae but decided to experiment and not do anything to remove it from some of the pots. He found the presence of algae to do no harm at all. His orchids didn't skip a beat. Can't remember the source, but he later told me of something he read in which it was hypothesized that the presense of algae might actually be beneficial as the oxygen released by the algae would be readily available to an orchid's roots. Just something to ponder.

[empiref]

Thank you all for your help!

[empiref]

I do not recommend the use bleach at all if the orchid is going to be exposed to bleach as well. If it is for empty pots then 1:9 bleach is good to disinfect and kill the algae. For Sh I recommend you use hydrogen peroxide 3%. Just pour it over the roots and let it drain. Also regular strong flushing with freshwater without any fertilizers should also get rid of the algae.

Amey,
Will hydrogen peroxide 3% get rid of the algae in the medium? or is it a fix for the plant?

[Halloamey]

Hydrogen peroxide will kill bacteria, fungii and algae. But you will have to be regular with the use, since only the dividing algae cells will die with the use of peroxide, intact mature cells won't be affected due to the strong cell wall ( the same reason orchid roots will not be harmed, but some developing root tips might be affected). I suggest treat with Hydrogen peroxide for about 15 to 20 minutes followed by a good wash and drain with pure water. Repeat every 5 days till the Algae vanishes.