Watering can be from either overhead or subirrigation systems.
Overhead systems include hand watering, sprinklers, movable booms, and trickle irrigation.
Subirrigation includes ebb and flood, flood floors, and capillary mat systems.
Sprinklers are a common form of overhead irrigation. It provides relatively uniform irrigation if the sprinkler head pattern covers the crop properly.
Its major drawback is that it can be inefficient if water that does not contact growing plants and through evaporation of water particles in the air.
Movable boom irrigation can use less water than sprinklers. It has the added advantage that the sprinklers are movable and not stationary in the bed taking up space.
Booms can have multiple nozzles with different size openings for either misting or irrigation.
Trickle or drip irrigation is a very efficient way to deliver water to container or field grown crops. Small amounts of water are applied directly to the root zone to limit water loss by evaporation or run off.
Trickle irrigation can be easily mechanized and with fertigation it can deliver soluble fertilizer during scheduled irrigation.
One form of drip irrigation uses small microsprinklers to deliver water to the root zone.
This directs water into the root zone.
Ebb and flood subirrigation systems place water in water tight benches and relies on irrigation water entering the container media through capillarity.
Water is held in the bench for a period of time to allow the media to become completely wet, then the irrigation water drains away into a holding tank.
Large greenhouse producers convert the entire floor of the greenhouse into a subirrigation system.
Flood floors water an entire greenhouse in one step. Flood floors were originally designed for pot plant production, but some growers are propagating plants by direct sticking cuttings on flood floors.
Boom irrigation is often used to supplements subirrigation until cuttings root.
Capillary mats are another form of subirrigation. Water is applied to the capillary mat which remains constantly wet. It acts as a constant water table supplying water to the media in containers that rest on top of the mat.
The advantage of capillary mat subirrigation is that media remains at a constant water supply without any intervening periods of drying. A porous plastic barrier prevents roots from growing into the capillary mat.