If the soil pulls away from the sides of the pot, the plant has dried out too much. Many houseplants need a wet-dry cycle. Water when dry to the touch. Too much water will suffocate roots. Know your plants' light needs.
Bright sun is different from filtered sun, and bright shade is different from light shade.
Light intensity affects the green pigment known as chlorophyll and affects the ability of flowering plants to bloom. Generally feed your plants once a month. If you tend to forget, use the fertilizer sticks that release food over 60-90 days. Products such as Green Leaf and Osmocote also release food over an extended time. For lush indoor plants, save the water used to boil vegetables and eggs, says Mary Stokes of Newport News.