Hard to say from the description - it could be mold or aphids. But older kale leaves will always get ratty. I would stop watering overhead and start watering at the base of the plants. Also kale does not need to be that warm. That might be contributing to the problem by promoting lush growth. It is a hardy vegetable and can cope with much lower temps. My suggestion would be to remove the oldest leaves and start eating the kale - it is a winter crop after all. I have had a nice picking from my outdoor curly kale this week. It was frozen crisp on the plants but cooked up beautifully.

Moisture and the dark spots you see is the mold collected on concrete surface pores.

The wood is fine. I like it. I dont like the yellow and blue walls. I would just pick what you want for colors and paint it. I do like your countertops, and I dont mind the floors, although, dont think the floors and the countertops really go good together. At least in your picture, they dont. The yellow walls added into the mix are too much. Maybe paint the walls white, and it will blend things together a bit more in the bathroom .

I’ve been having some unusual dark brown spots on my fiddle. It gets some good indirect sunlight every day, and I make sure it's properly watered and drained. Your plant definitely wants more than indirect sunlight. F lyrata is a plant that spends its early years fighting its way through the understory for its place in the canopy where it gets full sun. Your plant can be acclimated to tolerate full sun indoors, but a full sun position requires air movement. Surrounding leaves is a still layer of air (boundary layer) that acts as an insulator, trapping the heat generated when bright light strikes the foliage (passive solar gain). A fan will disrupt the boundary layer and allow the leaves to cool. If you decide to give the plant more light, gradually expose it to a heavier light load over the course of 10 days to 2 weeks. Your plant would LOVE being outdoors for the summer, and would enthusiastically show its pleasure should you decide to move it there. Morning and evening sun with shade at midday would be ideal. Again, the increased light exposure should be done gradually. And despite living in a clean apartment where there are never bugs, I’ve noticed some small flea like bugs hovering around it a lot recently. The insect appears to be a fungus gnat. They love wet grow media and rotting, vegetation, and organic fertilizers or soil amendments that break down quickly. I repotted it a few months back with new soil, so I wonder if there was some weird larvae inside of that. My guess is yes, or the wet medium is what attracted them. One gnat can turn into hundreds within a very short period. Now, about that grow medium ..... I see some chipped wood and bark on the surface, but the underlying medium looks severely compacted. It looks like the medium you chose when you repotted is excessively water-retentive, which would account for the gnats and the spoiled foliage. You can try using a "tell" to "tell" you when it's time to water, but proper watering won't fix compaction. What did it say on the bag of medium you recently used? Do you fertilize? With what? How often? I've noticed some white spots on top of the soil developing, perhaps some kind of mold? It probably IS dissolved solids left behind as water evaporated from the surface. Well-drained media generally don't get these deposits because they require water being wicked all the way to the surface from a larger reservoir held below in the medium. In fast-draining media, the water flowing over the soil surface dissolves deposits and flushes them out the drain hole. The surface of the soil dries very quickly because better media lack the ability to wick water all the way to the surface. What salts are deposited there from applications of fertilizer solutions are soon dissolved by the next application of water only, as already mentioned. The deposits might or might not be an indication of a salt build up in the medium; this because the deposit appear in very water-retentive media whether there is an abnormally high level of dissolved solids in the soil solution or not. If you habitually water such that a lot of water exits the drain hole when you water, it's doubtful there is any build-up of dissolved solids IN the medium; OTOH, if you water in sips because you already know the medium is too water-retentive, it's almost a certainty there IS a build-up of salts in the soil solution, especially if you fertilize regularly. Al