Black Spots on Monstera – House Plant Journal

Black Spots on Monstera

Plant Parent

Our Monstera plant has developed brown patches in the middle of its leaves. We thought it was due to over-watering, but changing the water schedule hasn’t helped.

Darryl

1) How long have you had the plant?
2) Show me the overall space where the plants live so I can see the size of the window and the relative position of the plant compared to the window.
3) What fertilizer (if any) do you use?
4) When was the last time you repotted?

Please let me know and I’ll do my best to help.

Plant Parent

Monstera for about 8 months (we used to water it 3x weekly and now 2x weekly)

The monstera is pretty far from the window but gets some direct light.

Just compost that we produce aerobically.

The monstera has only been repotted when we bought it.

Darryl

Your monstera, sitting so far from the window is receiving probably 10x less light than the ones close to the window – it’s not merely about less direct sun, the ***overall view of the sky*** is much less compared to being close to the window – that’s the main reason why there’s less light.

With less light, the plant is doing less work (photosynthesis and transpiration), which means slower water usage.

Given this poor light situation, watering at 2x weekly means the wet-dry cycle isn’t reaching the appropriate soil dryness level to require watering at such a high frequency.

Black rotted spots occur on monstera leaves when the plant is weak (from poor light) and the soil remains moist for too long from poor water usage (from poor light).

If you put the monstera right in front of those windows, you’ll see that the soil dryness reaches “partially dry” within about a week so if you wanted to water on a weekly schedule, that could work. I don’t have a schedule with watering my plants – I first make sure they get adequate light, then I just look at the soil and determine if it’s ready to be watered – nothing to keep track of.

Unfortunately, there’s nothing you can do to get rid of those black spots but they shouldn’t occur in the future if you move the plant right in front of the windows and water accordingly.

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