Can silver be used instead of Fungicide on plants? What would be safe?

everytime i plant potatoes, tomatoes, pumpkins, and any type of cubers i place a tablespoon of milk powder in the ground where the plant is going , that prevents powdery mildew and any fungal disease to attack the plant, also a tspoon of baking soda in a litre of water is ideal to be sprayed on roses, epsom salts can be added to the base of plants as an added bonus for minerals