For the person wanting to each others without electric about hydroponics manually, dont forget about the wick method where water is drawn up through a wick. You will need to tell them it dosent work as well for some plants that require a lot of water, or so i have been told. With the wick method they dont have to tend to it every day. This might help people who can not be at home to water regulary. Good luck by the way, on your ministry to help people in needy countries.