Whether you're finding your houseplants aren't looking very healthy, or you haven't seen any new growth over the spring and summer, it may be time to fertilize. As your plants live and grow, they absorb the nutrients and minerals in the soil. When these nutrients aren't replaced to keep your plants nourished, they may begin to show the signs of this malnourishment by not growing or flowering. If you don't know how to fertilize houseplants, don't worry; you can do it quickly and easily.
Read the instructions on your particular package of granule fertilizer, and decide how often you'll be fertilizing your plants. Often the fertilizer package will state two amounts to use: one based on fertilizing with every watering and another for fertilizing occasionally.
Fill a watering can with water up to the amount your fertilizer suggests, typically a gallon. Spoon in the correct amount of granule and mix together.
Water your houseplants as usual to introduce the fertilizer to the soil. If you have over watered, let the plant sit in its saucer or base for an hour before pouring off the excess water.
Use as frequently as the manufacturer recommends for the type of plants you have and the strength of the fertilizer, but do not over fertilize. Over fertilizing is known to "burn" your plants' roots and leaves and can harm your plants.
Observe your plants for a few weeks anytime after you fertilize them to check how well are responding to the fertilizer. Look for new growth and/or blooming to let you know your plant is healthy.