The surface of a compost plant is turning white for some reason. The white stuff is not fluffy and it looks like white powder or ashes. I had a look under the white stuff and it was perfectly normal. At this stage, I am not sure if it fungus or because it is getting colder.

I notice that the same is happening at the bottom of the pot where the soil is exposed to air in the holes of the pot.

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  • 1
    some of the white stuff looks like perlite, a common soil additive
    – kevinskio
    Commented Dec 20, 2015 at 23:23
  • 1
    Looks like you've got at least some fungus in there...
    – J. Musser
    Commented Dec 21, 2015 at 1:56
  • No, it's not perlite. @J.Musser do you mean compost fungi? Are plants at risk? Commented Dec 21, 2015 at 7:45

1 Answer 1


The white deposits look like salts from hard water. Very common when you aren't able to flush the through the pot completely.

  • Mmm could be. Could the salinity of the water be bad for the plants? Can I get rid of it? Commented Dec 21, 2015 at 21:44
  • If you are able to flush water through the pots rather than just add enough to get them wet, that will help.
    – Escoce
    Commented Dec 22, 2015 at 0:54
  • what do you mean by flushing water through the pots? Should I water my plants by mineral water instead of tap water? Currently, I water my plants using tap water. In a nutshell, tap water here is filtered sea water and have added chemicals such as chlorine. Commented Dec 22, 2015 at 18:17
  • No I meant give the enough water so that water pours out the bottom of the pot. However you will also probably want to age your water overnight. The day before, out your tap water into a bucket and let it sit overnight. Then the next day water your plants. If you can let the water run through the pot so the new water washes away some of the hardness from the previous watering.
    – Escoce
    Commented Dec 22, 2015 at 18:29

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