Definition - What does Sub-Irrigation System mean?
In commercial landscaping and container gardening, a sub-irrigation system is located at the bottom of the box or container. During sub-irrigation, water is applied to the bottoms of the plants and allowed to travel upwards to the roots and stems through capillary action. Because it does not require a lot of space, this type of irrigation system is often used in urban settings or high-rise buildings.
A sub-irrigation system is essentially a series of pipes and drip emitters buried beneath a plant's growing medium, and water is pumped to the bottom of the container, where roots find it and uptake it. This is opposed to traditional overhead watering systems, where water is applied to the tops of roots, and flows downwards.
MaximumYield explains Sub-Irrigation System
While it has been shown to have quite a few advantages, sub-irrigation systems can encourage an accumulation of soluble salts. This is because the soluble salts cannot escape into the lower soil profile. An accumulation of soluble salts can have a significant impact on the plant’s growth and development.
Despite this one disadvantage, sub-irrigation systems can be labor-saving while encouraging both water and nutrient conservation because water doesn't leach out of the container or planting box. Additionally, because plants receive water directly through their roots, this type of irrigation system prevents powdery mildew and other forms of diseases that form when the stems or leaves of the plants are overly exposed to water.
Most hardware stores carry products designed for sub irrigation systems under the brand names The Refuge Garden, Ollie Plant Sipper, EarthBox, and Planter Technology.