House plants need fertilizer just like all other plants specially since the nutrients in potting soil eventually get depleted and these plants are not getting nutrients from outdoor soil and rain. Do not wait until your plant is already looking "sick". Fertilizing needs to be matched with the specific plant, its age and how it is growing. Make sure you save all the information you received when you bought the plant. This should provide you a good outline of all its maintenance needs.

Plant food is made of three major components -- nitrogen, phosphoric acid, and potassium. It also contains a smaller amount of calcium, magnesium and iron. As a general guideline, green foliage plants need more nitrogen and flowering plants need more phosphorous. Most commercially sold fertilizers are labeled with the ratio of each of these ingredients and will need to be mixed with water. Select appropriately and make sure you follow directions exactly. If in doubt use a more diluted solution rather than less. Remember over-fertilizing, just like over-watering, can harm your plants greatly. But on the other hand if you do not provide sufficient fertilizer your plant will experience stunted growth and become unhealthy and weak. You can purchase time release fertilizers that come in a form of a spike that you embed into the soil for a specific amount of time. When time is up you just insert a new spike. This will ensure a hands off approach to appropriately feeding your plant.

Plants in lower light do not use as much fertilizer as plants that are in more intense light. General guidelines are to fertilize every two weeks during all seasons but in the winter as no significant growth is achieved during those months. Again, be sure consider the exact species of the plant you have. Most nurseries will be glad to help.