Cleaning green mold from leaves 🍃

[SADE2020]

Hi,

In the terrariums I am getting green mold or algae on the leave, not a super huge issue in terms of health, but compromise the photosynthesis and is not appealing at all. I have inquire with Spanish sources that live in South America forest, since I've seen that they deal with heavy mold and algea in the more humid month of the year. Almost everyone mentioned that the best recipe is to clean the leave with a calcium/mag, mustly calcium product diluted in water (1-2%).

Is it Kelpax/Kelmax appropriate for this ?

What's your opinion about this technique?

Any other option besides this in your practice?

Can this be used to clean dusty Phals leaves as well? (I know its no necessary but bugs me as hell, so if it can help with that, yuup even better). When I want them very clean I use milk.

Thanks and Cheers!

PD: Almost Here --》

[estación seca]

It's algal growth, not fungus. It wipes off with a tissue. It forms in terrariums more than in the wild for several reasons.

In the wild there will be rain, which washes things off the leaves. Algae are washed off before they multply much. In terrariums, most watering is far less vigorous than rain. In a tightly-closed terrarium it may be days to weeks between waterings, and gardeners rarely use heavy watering.

Ambient humidity varies more in the wild than in most terrariums. If the leaves dry completely for a few hours each day algae growth is less likely.

Ventilation in the wild is far better than in a terrarium. This also means leaves dry faster once wet. Dry leaves prevent algae.

Some combination of the above approaches would prevent the algal growth.

You can easily dust Phals with a soft cloth.

[SADE2020]

Thanks, ES.

As you recommended, I typically use a wet tissue or a little wet sponge 🧽 with plain water.

I want also to comprehend if rinsing with Calcium treatment avoids more growth, keeps the leaves cleaner, and helps with plant development.

I suppose it is similar to cleaning with milk, but my query is if KepMag will do it and if it happens to be beneficial
or would not compare to the Calcium solution they are talking about

[Shadeflower]

kelpmax is mainly micro nutrients so should be great for a foliar feed but dilute it at least 10 times more than if watering the orchid.

Use a solution of max 100ppm for leaves.

Leaves are very good at absorbng micronutrients, less good the macros.

Spraying the leaves with kelpmax is the fastest way to get the plant to absorb it.

It won't do anything to clean leaves, neither will calcium.

Bit of water should dissolve any residue. Anyhting that requires something stronger should not be on the orchid in the first place.

[isurus79]

Kelpmax will provide nutrients to the algae, so it won't be a deterrent. Calcium could act as a buffer to the water and help keep the pH higher than it would otherwise be if the calcium were absent, so it could produce conditions that the algae doesn't like. However, hard water with elevated calcium levels can leave spots on your plant's leaves, which might also be irritating to sade.

I've seen plenty of Cattleyas in high humidity environments covered with a thin layer of hard algae that doesn't wipe off. It doesn't seem to harm the plants. Unfortunately, I don't know how to remove that stuff.

I suspect you'd need a dedicated algaecide, maybe from a pet store used in aquariums. The algaecide might hurt the orchids though, so you'd have to test it out. I'd also try spraying rubbing alcohol on the leaves to see if the evaporating alcohol desiccates the algae. This is the same mechanism that kills mealy bugs when using alcohol. The moisture is pulled out of the bug's bodies and they die.

[Shadeflower]

stephen, very interesting. I grow indoors, no sprinklers so nothing gets on my leaves but I find it interesting you have seen so much build-up you couldn't wash it off.
Does surprise me a little. If anyone else has observed such encrusted algae I'd be interested.

I've had it on the sides of aquarium before but even there repeated wiping does loosen it. I'm interested as leaves can't get as much sun covered in algae like that. I'm just really surprised I've never experienced it before.

To me leaves act a bit like my Teflon frying pan. Anything just runs off it.

The exception would be my Rhyncholaelia digbyana, Aerides houllettianna or Rhyncholaelia Glauca.

They look like they are encrusted in Calcium and I know this will go on mute ears but I swear the stronger they get the less they add this "leaf protection" which looks like a bunch of sun screen dried on them. I have noticed that my nwest leaves on these are coming out completely smooth and green like any other Cattleya looks but when they are stressed they look like they were battered by ocean wind for the past year.

[SADE2020]

Thank you, Steve and Shade for replaying.

@Shade, btw I have no doubt that you can have algae on leave that won't go away with just rubbing water, especially in winter depending on your environment. I have seen it down in excursions in Costa Rica and the Colombian rainforest.

Just as @EstacionSeca was saying before in exterior wind dry everything fast but for some growers, with a "greenhouse" in the forest, is a real issue and they have clearly explained to me that when the leaf is covered with fine green algae it is very difficult to eradicate, even if you rub and rub.

The problem is that these algae when covering the whole plant leaves prevent the correct photosynthesis.

The thread is not actually about if the leaves get mold or algae at all, that I know...I am suffering the problem as we speak and rubbing water "is not enough" with all terrarium biggest leaves. (Phals, Bulbs Etc)

I understand using alcohol or peroxide water can kill it. I was trying to figure out if the calcium was effective as well and on-top beneficial, as those other growers have advised me.

Cheers!