Let’s talk about this garden! It looks simple enough, but upon further inspection, there’s much more going on.
We’d describe this garden as both “highly engineered” but also very, very simple. This is a sub irrigated system, sometimes referred to as a self watering garden. Specifically, we use a commercial kit called GroBuckets that turns a 5 gallon bucket into a sub irrigated planter. We absolutely love them and have a small fortune tied up into them.
Sub irrigation works on the concept of a reservoir of water being underneath the soil that puts the soil directly in contact with that water. The soil will effectively “wick” that water from moist to drier soils, keeping a nice, even moisture level across the entirety of the soil in the container.
Functionally, this solution is the reason we can grow off grid. The system increases our water utilization to nearly 100%, allowing us to rely on rain water almost entirely. It also solves a bunch of other problems with growing in containers as well, like reducing watering demands.
The GroBuckets are designed to be used stand alone. However, we pioneered a method to centrally irrigate them and we were quite likely the first people in the world to do so.
Essentially, we have an off-grid reservoir, made from a food safe Rubbermaid trash can that’s essentially done up like a rain barrel. We can put water or fertigated water in this reservoir. This reservoir flows into what’s called a control bucket, which uses a float valve to allow the control bucket to fill up to a specific level.
From here, there’s an outlet on the control bucket that goes into a manifold made from irrigation piping and parts. We mate this manifold to a low point on each bucket using what’s called a Uniseal. This all creates a water tight system which is very easy to put together and tear apart each season.
The other key component is that our containers are all at the same level. On our deck, this was easy, since it was all ready level. In our greenhouse, which uses a nearly identical system, we had to create a leveling system with concrete blocks and frames made from 2×4’s.
How this all works is by exploiting a principle in physics where water will seek its own level. The control bucket sets the water level, then eventually the level of the water equalizes across all of the buckets in the entire system at that same level. It’s complex because it involves understanding and manipulating physics, but its simple because it exclusively relies on a single float valve and gravity to work.
This keeps all of the containers in the system fully irrigated and basically makes them hands off, except for harvesting and refilling the reservoir occasionally.
We absolutely love these systems. Sure, it’s work to set up, but, then it’s a joy to watch grow. If there’s one garden we don’t have to worry about during droughts, it’s these. It’s pretty much gardening on auto pilot, at least as much as it can be!
