The need to fertilize houseplants varies with rate of growth, age of the plant, desire for growth, and growing season. Frequency of feeding can vary from every two weeks to every several months during the growing season. A general rule for application frequency is fertilizing at half the recommended strength, every 2 weeks from March to September. Do not fertilize most plants during winter months. Winter's reduced light and temperature result in little or no growth.
Most houseplants are dormant during winter.
Most houseplant fertilizers are fairly concentrated. Never exceed the recommended application amount. Oftentimes, applications should be even more dilute than recommended. Label recommendations are based on the ideal conditions in greenhouses. Spikes have the disadvantage of creating a high concentration of nutrients in the soil around them.