Your interior landscape contractor has recommended a sub-irrigation system for your new tropical office plants. What is this and is it necessary?
A sub-irrigation system allows a plant to take up as much water as it needs. It removes some of the guesswork from trying to decide how much water a plant requires. Although it seems this should be straightforward, there are many factors that affect this decision. A plant will never require the same amount of water every week. The temperature of the plant’s environment changes frequently, especially in an office building. The humidity also varies greatly day to day. When the heating system is on in the fall and winter, the humidity drops considerably, and the plant will require more water.The amount of light will change too. If there is a stretch of bright sunny weather, and the plant is located near a window, it may require more water. There are less daylight hours this time of year, and more cloudy days. When this happens, less water may be needed.
Horticultural technicians are trained to know how much water each type of plant requires and how to test the soil each week before deciding how much water to give a plant. The technician cannot completely anticipate the variables above though, so the plant may not always get the optimum amount of water at each service visit.
With an integrated sub-irrigation system, the plant has access to water at all times. The roots are close to the water, and it can take as much as it needs. We have found that this results in very strong, healthy looking plants.
Sub-irrigation systems usually consist of a reservoir for the water, and a platform to separate the plant from the water so the roots are not sitting in water. This would lead to root rot and the plant would quickly die. The roots grow through a layer of some type of substrate that absorbs water. Watering is done through a filler tube on the inside of the planter. A meter in the filler tube indicates the level of water in the reservoir.