Hydroponic apparatus comprises a hub member 44 connected through docking stations (58, figure 9) to a plurality of water-retaining hydroponic growing vessels 40. The central hub member includes connections to receive services including inter alia electricity air, water and nutrients from external sources and to supply each such service to each said docking station and from thence to each hydroponic growing vessel connected to the hub member. The docking stations may monitor the temperature and nutrient content of water present in each vessel and either alert the user to adverse readings or take remedial action. Also disclosed is an airstone (figure 4) comprising an internal chamber, with a removable open-topped upper section, a permeable membrane which extends over the top of the upper section of the chamber.
