A green roof, or 'living roof' really helps regulate the temperature of a house or building, keeping it cooler in the summer and warmer in the winter. You can even graze your goats on them! Indeed: goats can climb ladders, they are quite agile!
All you need is a small amount of vertical space around a balcony or an open window which can hang or store a vertical array of drink bottles that can grow all your herbs and lettuce easily. Recycle as many of your plastic drink containers.