Algae in Phal's clear pot

[Val]

Hi everybody,

I'm relatively new to orchids (6 months and 37 orchids). Although Phals have already begun to "speak to me", the algae are uninvited guests. I have noticed algae inside a couple of pots and I'm wondering:

1. Could algae be detrimental in any way to the plants?
2. What does the presence of algae signify? (Like to much / not enough light/humidity/warmth/watering/etc.)
3. Is there a way to eliminate algae without harming the orchid?
4. Are algae prone to expanding to neighbour pots?

And a somehow related question: doen anybody know an European equivalent of Physan 20?

MTIA

[Vanda lover]

From what I have read, algae won't kill your plant, but does compete for nutrients.
It could be that your potting mix is begining to break down and needs replacing.
If you don't think the mix is breaking down too much, you could try putting the pot inside a cache pot. Blocking the light should help reduce or even kill algae The roots look fine. Algae shouldn't spread to other pots unless the conditions are the same in them.

[Zoi2]

Algae grows when the conditions are good:light, humidity and food. It is not a problem for your plants other than it can get ugly. As Vanda lover says, block the light and it will not grow as rapidly.
Joann

[Jennyfleur]

Hmm, I have one phal which, being younger, doesn't have the root system around the inside of the pot that the others do (yet!). It has a little algae in the sides of the pot and the plant seems fine - it's nowhere near as much as yours, but it doesn't seem to be doing any harm. If it bothers you too much, then you could take the plant out, sterilise the pot and re-plant, but, like the others have said, it shouldn't be much of a problem for the plant

[BobInBonita]

I've never worried about algae. There are a few threads on water culture where it actually seems necessary for the orchids (theoretically by oxygenating the root environment).

[Ray]

You sure that's algae? From the photo it looks like it could be moss.

Either way, it is only an issue if it suffocates the roots, which isn't likely with algae; might be with moss. Any competition for nutrition is insignificant - algae even consumes some of the other plant's waste products.

Killing it in-situ will leave you with a cesspool of decaying matter in the pot. If you don't like it, repot.

[Val]

Thanks everybody!

@Ray: it's definitely algae - a very thin layer (less than 1mm).

I understand that algae are not a threat to the plant, they just reduce visibility through the clear pot.

I can slow down their growth by blocking light, but this will also block light to the roots - and I want my Phal's roots to get all the light they can get, so I decided I can live with it.

The safe way to get rid of algae would be to repot the plant in a new/serilized pot, which I'll do when the algae will become too dense or the plant/medium will require it - whichever comes first.

Good! That's one question down. Thanks again!

[RJSquirrel]