A long-time trusted houseplant fertilizer that provides pre-measured NPK in small, compact forms, these spikes can be pushed down into the soil to reach the root system, creating no waste or runoff. The spikes deliver multiple forms of nitrogen, phosphorus and potassium at a ratio of 13-4-5. The simple chart included tells you exactly how many spikes are needed per pot. This will feed your plants up to 60 days without the potential burning effects.