A few pots on the patio or a window box can become a dynamic mini eco system. A balcony garden can attract wildlife. With the right plants, a patio can hold an orchard. And it can all be done while 'thinking green' - using recycled materials when possible, being wildlife-friendly, choosing plants that will avoid waste, and gardening sustainably. This primer from the RHS guides you through greener choices when it comes to creating a container garden including materials, design, plant choice and troubleshooting.