One capful of Osmocote or 3 tablespoons are recommended for a 2 gallon pot, so if you are growing annuals in that 10-inch wide basket I would use a full capful on top of the soil. After sprinkling the product, work it into the very top layer of soil with a spade. Remember that hanging baskets and container gardens full of blooming flowers are heavy feeders and big drinkers. Check the soil daily to see if it is dry because the Osmocote will encourage root growth as well as flowers, and the new roots will fill the container as the summer wears on. The basket will need more water in July and August, than in May and June. Keep growing, Marianne Binetti