1. Try your brew on a few leaves of 1 plant and then watch them over the next few days. If there is no yellowing of the leaves, spray the whole plant. 2. Spray both surfaces of the leaves. 3. Spray once a week and if after a few days you don't see any results, then spray every 5 days. 4. In very hot weather, spray at the end of the day. 5. If it has been raining, wait for the leaves to dry before spraying.