Grotek Cal-Max, 4 Liter An excellent source of additional calcium, magnesium and iron, Cal-Max can be used on all plants, providing calcium, magnesium and iron for your garden This helps solve one of the most common nutrient deficiency problems facing fruit and vegetable growers as many soils or potting mixes simply do not have enough of those nutrients to keep the hungry plants growing Using Cal-Max as part of your regular feeding program will help to eliminate leaf yellowing or flowers dropping off