Growstone? LIFT is the ideal drainage layer for all your indoor and outdoor plants. Simply add LIFT to the bottom of your container and breathe fresh air into your roots. LIFT allows air to enter the inner core of your roots helping them dry evenly and allows excessive water to drain away. These highly porous large stones are lightweight, clean and provide aeration to roots superior to any other substrate on the market. The best part is they are made in the USA from 100% recycled glass!