A wicking bed is an agricultural irrigation system used in arid countries where water is traditionally scarce, in recent years they have become very popular amongst gardeners looking to save on water usage and still maintain healthy and productive crops. A wicking bed can be used inside a greenhouse and externally in your open garden with great success.
The systems are designed to increase food production while using approximately 50% less water than traditional irrigation, by utilising underground water reservoirs filled with decomposing organic matter and the process of evaporation.
Despite being an irrigation system, which can be fitted with automated refill capability via rainwater tank and float-valve if desired, it still remains relatively low-tech and functional.
There are a number of commercially available wicking bed products including re-cycled plastic wicking "cells" that are reported to reduce water use by up to 50% or more when compared to above ground irrigation.
There are a number of benefits to wicking beds, many of which arise due from the water moving upwards from below:
Watering from below produces less evaporation than top watered methods. Significant water savings are generated given the moisture gradient is the reverse of that from top based watering methods.
Plant roots seek out moisture. Deep watering is often recommended for this reason. Wicking beds have a moisture gradient that encourages roots downwards. This gives more stable plants that are healthier and less prone to water stress when surfaces dry out.
Lower Fungal Disease
The surface of a correctly constructed wicking bed is generally dry unless it has been raining. This means a lower level of surface fungal issues. This particularly benefits vegetables prone to fungal infections, such as cucumber, tomato, pumpkin and squash varieties.
Surface Pest Control
Slugs, snails and other pests prefer a moist surface. They find wicking beds more challenging to establish in and move between plants because the moisture is sub-surface.
Soluble fertilisers often wash through soil into the water table. However in a wicking bed, these are retained in the reservoir to be wicked back up through the soil. This means less fertiliser needed.