Editing Hydroponics (section)

===Run-to-waste===
In a run-to-waste system, nutrient and water solution is periodically applied to the medium surface. The method was invented in [[Bengal]] in 1946; for this reason it is sometimes referred to as "The Bengal System".{{sfn|Douglas|1975|p=10}}

[[File:Bengal System.png|thumb|A ''run-to-waste'' hydroponics system, referred to as "The [[Bengal]] System" after the region in eastern India where it was invented (circa 1946)]]

This method can be set up in various configurations. In its simplest form, a nutrient-and-water solution is manually applied one or more times per day to a container of inert growing media, such as rockwool, perlite, vermiculite, coco fibre, or sand. In a slightly more complex system, it is automated with a delivery pump, a timer and irrigation tubing to deliver nutrient solution with a delivery frequency that is governed by the key parameters of plant size, plant growing stage, climate, substrate, and substrate conductivity, pH, and water content.{{fact|date=March 2025}}

In a commercial setting, watering frequency is multi-factorial and governed by computers or [[Programmable logic controller|PLCs]].

Commercial hydroponics production of large plants like tomatoes, cucumber, and peppers uses one form or another of run-to-waste hydroponics.