Over the years fresh flower foam has been perfected to have proper PH levels and specific cell structure to allow water hydration to occur. The flower foam holds a limited amount of water for the flowers placed into it. If the flower foam does not have an ample reservoir of water the flowers can suck out all the water. Tests have shown that flower foam, while providing an artistic option does not allow flowers to last any longer than water. Some varieties of flowers such as roses do not last as long in flower foam as they do in plain flower nutrient water.