Question
I have had a pothos in my living room for a few years. A couple years ago I noticed when watering a scummy film with a chemical smell would rise to the top and float on the water. I kept trying to water it out but each time it was there. A year ago I re-potted with new potting soil (Miracle-Gro)and now it's doing the same thing again. Can this be from the plant pulling toxins out of our environment and it is coming up in the soil? I know they are known to clean interior air but this is really nasty.  Any ideas for me?  I'm ready to re-pot again but thought I'd get some expert advice first ;)  Thanks!

Answer
Hi Mary Lou,

Any chemical removed by the plant from the environment would never be visible, so that is not what you are seeing.

There are three possible sources of the scum you are seeing - the soil, the water you are using or the material the pot is made from.

Miracle Gro soil is often infested with fungus gnat larvae, but I have not heard that it is contaminated in any other way. Water quality is important. If your tap water is on the hard side (high mineral salt concentration), then that is likely to be the cause. If so, use filtered or distilled water instead. And if you have been adding fertilizer, stop. Make sure you are allowing the top quarter of the soil to dry out before adding any water.

I don't know what kind of pot your plant is potted in, but certain metals can interact with the chemicals in the soil and cause the problem. It is also important that the pot is relatively small and has a drain hole that allows excess water to drain out.

Finally, make sure no one is adding anything to the soil. I know some folks add beverages (coffee, tea, soda, etc.) to their plants and that is NOT a good idea. Pets have also been known to use plants as a potty.

Please let me know if any of this is unclear or if you have any additional questions.

I have written an article on Pothos care that I will email email for free to you (or anyone else) who emails a request to me at [email protected].

If this information has been helpful, please click the Rate Volunteer bar below and enter a rating and NOMINATION for me. I am a volunteer on this site so Ratings are the only compensation I receive for answering plant questions.

Need more information? Visit my website at:
A link to HorticulturalHelp.com

or email me at [email protected] or call me at 917-887-8601 (EST)
 
Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

Visit my website at: A link to HorticulturalHelp.com

Regards,
Will Creed
Horticultural Help, NYC
Cell: 917-887-8601

Visit my website at www.HorticulturalHelp.com