Self-Watering Systems

Whether you want to produce one plant or several in one system, self-watering containers (SWC) are incredibly effective, convenient, and economical.  Self-watering containers use water from a reservoir to keep the growing substrate (soil, soilless mixture, potting mixture...) at what is called Field Moisture Capacity (FMC) through Capillary Action.  Growing substrate (GS)  has macro-pores and micro-pores.  Macro-pores are "large" openings within the GS that readily allow air and water to flow through.  Micro-pores are "small" openings in the GS that generally hold water and is where plant roots acquire water from.  Field Moisture Capacity is where all the micro-pores are filled and all excess water has flowed through.  Field Moisture Capacity creates an optimal root environment by providing oxygen through the macro-pores and water through the micro-pores.  Capillary action can be compared to diffusion in liquids where a substance of high concentration moves to an area with low concentration until equilibrium is reached.  This occurs in the GS in the same fashion, water moves from areas of high saturation to areas of low saturation.  Capillary action is the process that allows a Self-Watering Container to work.

The concept of Self-Watering Containers can be applied in many situations.  A very simple application would be a bottom watering system.  This system is quite basic and effective.  It works by setting a potted plant in a tray of water, that's it.  The water is taken up into the pot until FMC is reached.  As the plant takes up the water from the GS it is replaced in the GS from the tray of water.  The potted plant can be removed from the water after FMC has been reached and another plant can replace it.  This is a very basic version that can be expanded upon in many ways, all with the same benefits:

1. There is not moisture on plant surfaces which can result in disease
2. There is no splash up of soil onto plant surfaces which can result in disease
3. The plant receives the perfect amount of water while still having access to oxygen
4. Watering is no longer a guessing game (Did I give the plant enough?  Did I apply too much?)

Ok, now that we have the basics down let's take this one step further, the Self-Watering Tray (SWT).  The SWT is great for growing lettuce and salad mixes, peas, chives, propagating cuttings, and many, many other food crops.  The following video details how to make a SWT using two greenhouse flats, cloth, clothesline, and PVC piping.

Self-Watering Tray Video

This same concept can be applied in many different situations. The Wick can be nearly any length and the top tray can be any plant container or several plant containers.  The reservoir can be any shape or size and can be attached via a float valve (like a toilet float valve, a float valve in this context can be used to fill a reservoir when it drops below a set level) to a larger reservoir.  This larger reservoir can service several smaller reservoirs.  The beauty of this is that the reservoir can be filled and the plants will not need to be watered until the reservoir runs low.  What does that mean?  You can go away for the weekend and have no worries, house sitters can simply fill the reservoir (worry-free vacationing), you can take care of your plants on an every-other-day basis if your schedule demands so, and best-of-all, your plants will be growing in a system that provides the optimal conditions for plant growth!

To sum up - Self-Watering Containers:

- can be any shape and any size
- can be made very cost-effectively
- provide optimum conditions for plant growth.