Looks like fungus infection. Isolate the plant and remove the affected leaves.
I'm wondering whether this could be due to too high humidity
Regardless of what it is. Quarantine the plant. I had a similar issue and it spread to two other plants.
Sorry, not gonna be much help as I don’t have an answer... Anecdotally, my many Jade plants grow very well while inside near a south facing window (I’m in the northern hemisphere). Maybe it has to do with the grow light or over watering?
Thanks for all your suggestions! I isolated the plants for now (and moved them away from the plant light) and I will try to get rid of the affected leaves gradually.
I noticed small white dots on the leaves, which makes me think that it might actually be lice. Although I never saw one move, so not sure about that.
Hopefully my poor jade plants will recover.
Small white dots could also be chalk from your watering water
Succulents
Welcome to !succulents@midwest.social, where you can share and converse about anything succulents.
If you’re interested in participating, please subscribe.
Rules: Be respectful and civil. No racism/bigotry/hateful speech.