I've grown philodendrons in water for years in all sorts of light conditions and never had an algae problem until taking a cutting to work a few months ago, where the whole glass container rapidly starts to turn a neon green color not long after being freshly cleaned out.

Is there something I can use to continue growing a healthy plant in water but preventing algae growth?


1 Answer 1


Algae grows where there is light and nutrients. Most plants can absorb the nutrients found in tap water more efficiently than algae if they have roots. Here are some ideas:

  • use a cup or other container that is opaque to light. If no light goes in, algae growth will be reduced.
  • if they are in a high light, higher temperature area move them to a lower light area.
  • reduce any sources of more nutrients and spores. Putting the container next to an open or screened window will allow millions of airborne particles to settle on the water and become algae food
  • see if the problem is less pronounced for plants with an established root system
  • regular cleaning of the container until the plant is established should keep the algae in check. A one time cleaning with water and a bit of and bleach might help.

And yes, there are chemicals that pond owners add to water to reduce algae bloom but this seems like overkill for a problem that good practices can control

  • Thanks for the answer. I'm more curious about the chemical options still because the plant is in a fully-sealed indoor area on an upper floor of a building with no open windows ever. I'd also prefer to keep it in a glass cube-shaped container for style reasons. Lastly, the root system is rather large and impressive. On the last count, though, it does at least seem like there's possibly slower algae growth than when the root system was smaller.
    – UtopiaLtd
    Apr 20, 2012 at 16:40

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