Osmocote plant food should be used at least once a year on indoor plants but use half the recommended amount that the instructions suggest for outdoor plants. Plants in pots grown indoors get less sunlight and their roots are constricted so they grow at a slower pace and need less fertilizer. This is a general guide for most indoor plants. Houseplants that bloom or that are grown in a sunroom or greenhouse may need more fertilizer but never exceed the amount printed on the label. The size of the container and the size of the plant also determines the right amount of fertilizer. I generally use one half of a teaspoon for a houseplant in a container that is 6 to 8 inches wide.  More for a plant in a larger pot, less for plants in smaller pots. When I transplant into a larger container I will mix Osmocote into the potting soil but for a plant already growing in a pot just sprinkle the Osmocote granules on top of the soil then work them carefully into the top half inch of soil and water. The Osmocote granules will slowly release the nutrients over 6 to 9 months depending on how often you water and the soil temperature. When spring arrives I like to fertilize larger indoor plants again as the addition of more sunlight makes them grow faster so they use more nutrients. Don't' worry too much about getting it perfect when you use a slow release plant food like Osmocote. The advantage of the time release pellets is that the plants take only what they need so you won't risk burning the plants from too much fertilizer. Keep growing, Marianne Binetti