I dont know who needs to hear this, but don't trust shitty "plant health" apps that give off the walls advice like pouring milk or sugar water into your plants.
Most indoor plant problems are gonna come down to:
Too little or too much light:
-If its lanky (growing tall thin and weak with not a lot of leaves or buds), pale, or droopy it may not be getting enough light. Figure out which windows face south and west, or will otherwise get the most direct light. If its been in high shade do this slowly over a few days to avoid burns
-If its leaves look pale and reddish, especially after a move to more light, it could be sunburn. If its a high light needing plant it could just be shock from the move out of shade, so see if it worsens or bounces back. If it keeps looking sickly and drying out too fast, move it somewhere with northern/eastern or more indirect lighting. Remember plants will still need SOME light source
Too wet or too dry: Limp and pathetic looking - stick your finger into the dirt and see if its moist 1" down
-If its moist DONT water it may have root rot and needs to dry out. Move to a sunnier spot and water less.
-If its dry, add water and watch to see if it absorbs or flows right out of the bottom. If it does, your soil may be hydrophobic and the pot needs a good soaking in a bottom-watering tray & more regular watering.
Too much or not enough nitrogen:
-Knowing how long this soil has been used (most "potting soils" aren't real soil and run out of available nutrients in about a year) and if youve ever added fertilizer or nutrients will tell you the most here
-If it's old soil 1.5 yrs + you can uppot into a larger pot with fresh soil or shake out and slightly trim the roots and repot in fresh soil.
-If lower leaves are yellowing and higher leaves are yellowing at the base, its lacking nitrogen & needs a good dose of fertilizer. Nitrogen is the first number on the 1-2-3 lists on fertilizers, get one higher in nitrogen (not JUST nitrogen) and follow directions so you dont burn your plant
-If leaves are getting much darker green or seeming to burn out at the ends without any additional sunlight, or yellowing like above and you know youve added nutrients recently, it could be too MUCH nitrogen - shake out roots and put in fresh soil, if you really cant do that then run water through the soil for a while because nitrogen is water soluble and will be flushed out
Pest or disease: Treatment varies a lot based on what's wrong, so look for clear signs of predation (leaves eaten, hole-y, or have translucent tunnels inside, poop, webs, bubble spit nests, actual pests themselves) or disease (mildew spots, rotting leaves, discolored spots or splotches, leaves curled) and find a good resource to narrow down what it is. In the USA your local university extension should have a pest problems page, for Oregon its OSUs solve pest problems site. Good general practices are keeping things pruned to allow in good light and air flow, while removing diseased or infected areas - use rubbing alcohol to disinfect between/after diseased cuts
Thats it. Thats the common problems. Too much or not enough of what they need, and sickness/pests. All of them are simple answers, at least to start troubleshooting with. None of them include dumping milk or sugar that will drastically change the soil microbiome, restrict water/nutrient uptake, and GIVE YOU ANTS.
If any app is advising you to START solving a problem by 1) buying something or 2) dumping a bunch of random shit into what is essentially your little mini dome of life - RUN AWAY!!! There's a difference between specific home remedies that involve mixtures of say 1:10 milk to water only on the leaves for mildew, or dumping a whole cup of milk in. There's a difference between some light compost or fermented fruit tea from your old banana peels, and dumping sugar water or pure coffee into your pot. We are not baking a cake we are feeding a PLANT with roots that take in specific things, not a stomach lining. This goes TRIPLE for any "weeds advice" that tells you to dump vinegar or salt on an area - itll kill your weeds, and everything else.
Just. Dont trust anyone who's advice is "pour a bunch of random shit on there," especially if its an app thats supposed to be figuring out from NO CONTEXT which of the causes could be making these leaves yellow.
