Emerald Harvest Cal-Mag Supplement 5.11 lbsIn Store Location: @B18 Keep your plants productive and green with Cal Mag, a calcium and magnesium supplement from Emerald Harvest. Containing top quality ingredients, Cal Mag is designed to nourish crops with extra calcium and magnesium and create the right conditions for abundant flowering and a heavy yield. This is especially important when growing in some media, such as coco coir, but any garden can benefit. Use Cal Mag as a supplement to a base