In Germany, where water for agriculture gets scarce, some farmers are adopting methods that I consider semi-hydroponic. For example burying a soaker hose below

In Germany, where water for agriculture gets scarce, some farmers are adopting methods that I consider semi-hydroponic. For example burying a soaker hose below the crops. However, "real" hydroponic systems need to be protected from rain, I think, because rainwater would dilute the nutrient solution if it leaks into the system.