Feed houseplants with Miracle-Gro® Indoor Plant Food Spikes. Each plant food spike contains the micronutrients that indoor houseplants need. These are safe (when used as directed) for all indoor potted plants including ferns ficus spider plants snake plants pothos and crotons. Use the handy ruler on the edge of the package to measure the size of your pot and determine the number of spikes needed and then using the Miracle-Aerator spike simply make a small hole in moist soil and insert the plant food spike. All that s left to do is sit back relax and enjoy your happy houseplants. In spring and summer spikes should be replaced every 30 days while in winter and fall wait 60 days before replacing them. Each package comes with 48 spikes. Continue to water your plants as needed. Miracle-Gro® Indoor Plant Food Spikes promote lush foliage and beautiful blooms. You can feed and grow stronger (vs. unfed) houseplants with Miracle-Gro®.