Can someone tell me what's wrong with my plant?
My initial reaction is too much water, too little light. That pot can not possibly have a drainage hole if you feel comfortable enough to set it on this furniture.
Without drainage, a hole, no rocks at the bottom of the soil making a perched water table, water will not be 'pulled' out of the soil being replaced with air. Allowed to 'dry' out enough to not be promoting fungus and anaerobic conditions.
This will compromise the roots. Rotting them, not allowing proper up take of water and chemistry necessary to be distributed to the plant's photosynthesizing factories.
I would purchase plain old potting soil and a basic 10" clay pot with drainage hole and saucer (find pieces of tile or buy cute pot feet). Turn that plant on its side, pull it out of the pot, gently shake off as much wet stinky soil as possible without damaging the few roots still healthy. Cover your plant and roots with newspaper while doing this. Fill pot 1/3 or what ever is necessary to ensure the top of the root ball is within 1 1/2 " of the rim of the pot. That first 1/3 of soil is just potting soil installed right over the drain hole (use a thin piece of panty hose over the hole if you are worried about soil falling out as it will at first, later you can drag that panty hose out), FIRM that 1/3 bit of soil, then spreading the roots a bit, place this plant on top. The crown of the roots that should be covered with soil, should be 1 1/2 inch below the rim of your pot. An inch is great. Any less rim will make watering tough to do.
Firm gently to remove large air pockets, moisten lightly. Cut off all leaves that are brown, yellow, damaged as close to the main stem as possible. No stubs. Keep your indoor plants in one spot as much as possible. It is stressful for indoor plants to be moved to different spots that differ in light and temperatures, drafts are a big deal. So are forced air vents. Only water when your plant and pot when you lift are light. Get used to the weight of your pot and plant when watered and you'll be able to tell easily when to water again and not sooner.
Do not add anything else to the sterilized potting soil. Oh, except a little fertilizer such as Osmocote 14-14-14 extended release. I use the recommended amount but only do half the applications. I think they say add every 3 months. I only add more at 6 months. This is the fertilizer I always recommend because it is hard to make mistakes. Make sure you have no added fertilizer (by the company) in your potting soil. No compost. Nada. I also use distilled water I buy at the store, unless I have my own well water. Tap water is horrible stuff.
When you pull your plant out of its pot check the roots. Pull or cut off any brown or slimy parts.
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