Large Multiple occupancy buildings should utilise roof space by building a greenhouse with adequate growing area for a large number of fruit and veg, such as tomatoes, courgettes, lettuce, etc. Residents can place their uneaten food in a compost bin in the bin stores and rainwater can be harvested for watering. Excess heat generated by the building can be used to heat the greenhouse during winter allowing for sufficient growing conditions all year. Produce can be delivered back to residents and upkeep would be paid for by a small extra cost in maintenance charges. This would create a self sustaining ready supply of healthy food. This would also result in a C02 reduction due to the elimination of the need to travel to shops, or for the large scale production of crops bought in a supermarket.