Farm station gets filled with 50kg of fertilizer, then gets ignored. Assigning farmers doesn't change anything. The room is designated as greenhouse, but no effect can be seen on the plants.
Tried on bristle berries and mushrooms. Also on mealwood, but it isn't listed among plants that should get the boost. On planter boxes, farm tiles and hydroponics. With both farmer and seasoned farmer.
Build farm station, assign a farmer, build a greenhouse around it, plant plants. Observe lack of "tending to crops".