Bucket irrigation system. Could be hung on an old clothesline post. The article mentions filling the buckets with water, but I would use it as a rainwater collection system. Close the valve on rainy days then open it when the garden needs water.
Solar powered, programmable rain barrel irrigation system that babysits your garden while you are away. The system operates by collecting its own renewable water supply from captured rain water and its own power supply from the sun. Here Garden Sitter is powering the drip system (60' long) at Halsey's Nursery in Edenton.