Epsom salts in the soil for tomatoes and peppers. Add a Tablespoon or so in the soil when first planting and then sprinkle more into the soil when mature.
Spraying epsom salt on plants boosts magnesium supply to plants and increases yield. Spraying 1 table spoon of epsom salt mix with 4 litre of water twice with 10 days gap could be used for good results. Tomatoes, peppers and rose can benefit extraordinarily