Darryl

Light and watering are always connected. Your plant is seeing a very narrow view of the sky from that position, so its photosynthesis rate isn’t as ideal as it could be right in front of the window. Once you have measured light indoors with a light meter, you will understand the drastic difference a few feet can make.

Given that your lighting situation is suboptimal, the water usage in the soil has been sluggish. Over time, overly moist and stale soil are likely to give rise to fungal issues, like these black spots, which are permanent.

Three things you can do to mitigate future black spots and improve the overall health of your Monstera:

1. Give the plant the widest possible view of the sky and if the sun happens to shine directly on the plant for longer than 2-3 hours, then you should block it with a white sheer curtain.

2. Check the soil to a depth of 2-3 inches to see if it is dry – that is the cue to water (not an arbitrary schedule based on the type of plant).

3. Occasionally, you should gently loosen the soil with a chopstick before watering. This will do two things: it will bring oxygen down to the root level and it will allow the water to more evenly penetrate the soil.

You’ve got a very nice Monstera! Good luck!