Fern plants like to stay moist, so it's important to mist them regularly with water. For use, fill the atomizer with water, carefully add eight drops of fertilizer and shake. Spray the leaves during the growing season (May to September) once every 2-4 weeks. Each set contains 100 ml of natural plant food, designed to last for about a year. The plant food was made using nutritious seaweed collected from a beach near Norfolk. Seaweed is a wonderful fertilizer because it is rich in nutrients and carbohydrates, helping your plants to grow strong and healthy.