I tend to use compost as a fertilizer in the spring. Just mix it into the soil. During the summer season, I add old teabags to the soil, or used loose tea leaves. Also, I use leftover tea to water my plants in the house. We are big tea lovers and there is always a bit left in the pot. I add water to fill the pot, and water my plants. It acts as a fertiliser.....my plants are now tea-lovers too!! And they look great!!!