A soilless plant growing system, comprising: a conveyor for moving plants around a closed loop, wherein the conveyor is a floor-mounted conveyor located in a growing room that is held at a first predetermined set of environmental conditions; the growing room being a clean room in which the conveyor is located, the clean room provided with a filtered air supply and held at a pressure above ambient atmospheric pressure; a plurality of carriages configured to be mounted on the conveyor for movement thereon; an automated carriage apparatus to remove a carriage from the conveyor and/or insert a carriage onto the conveyor, wherein the automated carriage apparatus is in the form of a spur line with switchable points to move a carriage of the plurality of carriages off the conveyor and move it to a crop handling area that comprises a further clean room, wherein the crop handling area is held at a second predetermined set of environmental conditions that are different from the first predetermined set of environmental conditions, wherein the second predetermined set of environmental conditions include a light level of substantially zero, and wherein a cleaning station is provided adjacent to the spur line for cleaning the carriages; at least one tray configured to be received on each of the plurality of carriages, each tray configured for growing at least one plant in the absence of soil; at least one watering station configured to irrigate the plants on each carriage as the carriage is passed adjacent to the watering station, wherein the watering station is configured to collect water run-off from the plants and to purify water run-off collected from the plants by using filtering and another purification method of chemical purification, using UV light and/or living organisms; and an automated tray apparatus to remove and/or insert a tray from and/or onto carriages of the plurality of carriages. a conveyor for moving plants around a closed loop, wherein the conveyor is a floor-mounted conveyor located in a growing room that is held at a first predetermined set of environmental conditions; the growing room being a clean room in which the conveyor is located, the clean room provided with a filtered air supply and held at a pressure above ambient atmospheric pressure; a plurality of carriages configured to be mounted on the conveyor for movement thereon; an automated carriage apparatus to remove a carriage from the conveyor and/or insert a carriage onto the conveyor, wherein the automated carriage apparatus is in the form of a spur line with switchable points to move a carriage of the plurality of carriages off the conveyor and move it to a crop handling area that comprises a further clean room, wherein the crop handling area is held at a second predetermined set of environmental conditions that are different from the first predetermined set of environmental conditions, wherein the second predetermined set of environmental conditions include a light level of substantially zero, and wherein a cleaning station is provided adjacent to the spur line for cleaning the carriages; at least one tray configured to be received on each of the plurality of carriages, each tray configured for growing at least one plant in the absence of soil; at least one watering station configured to irrigate the plants on each carriage as the carriage is passed adjacent to the watering station, wherein the watering station is configured to collect water run-off from the plants and to purify water run-off collected from the plants by using filtering and another purification method of chemical purification, using UV light and/or living organisms; and an automated tray apparatus to remove and/or insert a tray from and/or onto carriages of the plurality of carriages.