Croton plant care
My Croton plant is developing dark bruise-like spots on the stems of its leaves, and is dropping leaves too. What could be the cause(s)? Room temp is 68 degrees F, indirect but bright light, but I have to move it to kitchen sink to water it.
Dark spots on stems sounds like some kind of fungal disease. I would pull the plant out of the pot and check the roots, looking for dark brown and/or mushy roots, which would indicate root rot. If you see these, you can wash off the old soil, trim off the dead roots, and repot using a well-drained potting mix (I personally use half and half cactus soil and perlite.) This article has more information: https://www.gardeningknowhow.com/plant-problems/disease/treating-root-rot-gardening-tips-for-housplants.htm
Even if you don't find extensive root rot, you may be overwatering. Testing the soil near the bottom of the pot, the soil should be lightly damp, but not wet. Even if you don't water until the surface of the soil is almost dry, water may be held farther down, closer to the bottom of the root zone. And that overwet can be reflected in browning of the leaves and/or stems. This article tells more about testing soil moisture: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-moisture-in-plants.htm
Another thing you can try is moving your plant to a spot with a bit more light. I have often had to move a houseplant from spot to spot until I found its "happy spot." This article has more info on growing croton in the house. https://www.gardeningknowhow.com/houseplants/croton/care-croton-plants.htm