15 grams of laboratory grade agar agar powder will yield 1 liter of solution (approximately 40-50, 100mm x 15mm petri dishes). Please note: agar agar is the base ingredient for making laboratory growth media. If you are interested in purchasing growth media that includes nutrients you need to purchase "nutrient" agar (http://www.amazon.com/gp/product/b008ye69ig) or a "nutrient" agar kit (http://www.amazon.com/gp/product/b00b799pdg). Please search our other listings for nutrient agar or send us a note if that is what you are looking for. If you have any questions please send us a note and we will reply within 24 hours 7 days / week. Thanks for looking!