This was inspired by another instructable that shows how to build your own earthbox. My design adds a gravity fed, zero power consuming irrigation system that can water multiple containers automatically.The whole project is built using common, easily found parts at potentially zero cost.
I live in an apartment that doesn't have a garden, but I do have a small roof outside my bedroom and I wanted to start a vegetable container garden on it. The idea of self watering containers appealed to me, but even with self watering containers I would still have to crawl out my bedroom window with multiple buckets of water every few days to keep the containers full.
What I needed was a way to keep multiple containers watered from a central reservoir that was easily accessible. I couldn't just connect the feed tubes straight from the containers to the reservoir because then it would just empty out, unevenly watering the containers and over watering the plants. However I didn't want wires hanging out my window, so I didn't want something that required electricity. It also had to be simple, so it could run with no need to dig it up and fix it, and it had to be cheap (or free), so I could repeat it on multiple containers and expand my garden without spending a lot of money.
The containers I've designed use the same self watering system as the earthbox concept, but I added an automatic shut-off valve to each container so that multiple containers can be gravity fed from the same reservoir. Each container regulates how much water it takes from the reservoir so, however many containers you have in your garden, all you have to do to keep them all watered is to make sure the reservoir stays full, no need for electricity, pumps or timers.
Construction is fairly simple and all parts are readily available for very cheap (almost all are very common and could be found for free if you are so inclined).
If you do decide to buy all the parts, it will set you back about $10-$12 per container
Step 1: Parts
What you will need for each container, (almost all parts are available at a good dollar store, except maybe the hose and hose connectors which you can get at a hardware store):
- A container with a lid (can be anything, I used two 5-gallon buckets and a big rubbermaid storage box).
- A plastic colander or basket that fits with plenty of room into the bottom of your container.
- A small rectangular tupperware container that can fit alongside the above mentioned basket in the bottom of your container.
- A toilet ballcock mechanism, the simplest, cheapest type with the float on an arm.
- A rubber ball that floats
- Some small gauge threaded rod (or you can just use the arm that came with the ballcock mechanism, if it can be cut down)
- A few feet of hose
- A nylon hose barb the same gauge as your hose (and barb T's, to add extra containers)
- Waterproof adhesive in a caulking gun
Step 2: Constructing the False Bottom
This is the part that borrows from the original earthbox idea.
You want to make a false bottom to your container, creating a separate chamber in the bottom with a hole cut in it for the colander or basket to sit in.
The original earthbox instructable suggests doing this by placing one container inside the other. This is fine, but I'm a cheapskate and I don't want to have to use two containers, so I just used the lid that came with the container.
1. Trace the outline of the basket on the lid
2. Trace the outline of the tupperware container alongside it (note: In the picture this is a circle, but this was for the first version of this project which didn't work, yours will be a rectangle)
3. Trace around the bottom of the container onto the lid to create the edge that will fit into the container
4. Cut out the container outline and the two rectangles
(construction note: when I cut the lids of the 5-gallon buckets I used all purpose snippers and discovered that the material is waxy and cracks easily, so cut carefully, the cuts don't have to be exact or tidy and most cracks can be fixed when you mount it, but you don't want the material to crack completely)
Step 3: The Shut-Off Mechanism
This is the fun bit.
We're going to use the ballcock assembly to make the shut-off valve, but since the water will be coming from the top, not the bottom (as it was designed to do), we're going to have to flip the valve around so that the fulcrum is on the other side.
Also, this whole assembly is going to fit inside the small tupperware container so the float arm will have to be shortened and a new, smaller float put on the end.
This may seem a bit complicated at first, but if you read through all the steps and understand what you are trying to achieve in the end it's actually pretty simple and can be adjusted for the specific design of ballcock mechanism you have. Also, once you've done one you'll be able to do additional ones pretty quickly and easily.
Step 4: Shut-Off Valve Step 1
Take the float arm off the assembly, take out the top adjustment screw and remove the fulcrum pin of the ballcock valve mechanism so you can remove the top lever.
You will probably have to cut off all extra bits to pare the lever down to a basic block, so that it will still be able move freely when you flip it around.
Step 5: Shut-Off Valve Step 2
You will have to drill new holes for the adjustment screw and the float arm in the other side of the lever so that you can flip the lever the opposite way around.
1. Drill a new hole for the adjustment screw in the other side of the lever.
2. Depending on the exact design of the ballcock valve, you may need to drill a hole for the float arm in the opposite side of the lever. If the mechanism you are using has a metal arm that screws into the valve lever, you may not have to do this as the hole is already there.
3. You will probably need to drill a new hole for the fulcrum pin so that the adjustment screw sits on top of the valve when the lever is reversed.
Step 6: Shut-Off Valve Step 3
Cut off the feed pipe of the ballcock assembly about an inch from the valve.
Step 7: Shut-Off Valve Step 4
Mount the lever, reversed, back on top of the ballcock valve (I used a nail bent and snipped off at one end as the new fulcrum pin).
1. Screw in the threaded rod (or the original float arm if your particular ballcock assembly allows)
2. Cut off the float arm so that the whole thing fits into the tupperware container.
3. Screw the rubber ball onto the end of the arm as the new float.
Step 8: Shut-Off Valve Step 5
Cut a hole in one side of the bottom of the tupperware container so that the new valve can fit inside with the shortened feed tube sticking out the bottom.
Use the waterproof adhesive to glue the whole shebang into the tupperware so the feed tube sticks out the bottom. You may have to bore out the feed tube so the hose fits snugly into it.
Also, you will want to fill in the secondary, smaller feed tube with adhesive otherwise the water will come out of there too, and probably fill your valve mechanism with dirt.
Voila! You have a miniaturized float shut off valve in a box, and you only had to cannibalize one toilet to make it.
Also, you are going to want to screw the adjustment screw all the way in so that as soon as that ball starts floating the valve will engage.
Step 9: Mount the Whole Thing in the Container
Using the waterproof adhesive, glue the basket onto one side of the cut out lid from step 2, and glue the tupperware containing the valve mechanism onto the other side.
1. Stick the whole thing, basket side down, into the container and glue it around the edge to seal the false bottom in there nice and tight (don't worry it doesn't have to be watertight or anything, you just don't want the bits to move around when you put the soil in).
2. Drill a hole in the side of the container above the valve feed and screw in the hose barb so it sticks out the side of the container.
3. Connect the inside of the hose barb to the valve feed with a bit of hose.
(Note: If you want to save money on those expensive hose barbs, you can just drill a hole and have the hose sticking out the side, I just like the barb because it makes the container easily connected and disconnected to a group of containers. Also, there's no reason you have to put the hose out the side of the container. You can have the feed hose just stick out the top, I just wanted to make sure that the feed is below the level of the reservoir without having to put the reservoir up too high.)
You may notice in the picture that my container is a big mess of adhesive, that is because this project went through several incarnations before I found a shut-off mechanism that worked properly (the one I have described in this instructable). Each of the three versions I went through was torn out and retrofitted with the next, resulting in an ungodly expenditure of adhesive as I had to fix where I had cut before. Yours should be a lot neater, but even if it isn't, it doesn't much matter since the whole thing will be buried under soil anyway.
Step 10: Connect All Your Containers to a Single Reservoir
1. Get another container (your reservoir), drill a hole in the side at the bottom of the container and screw another hose barb into it
2. Using the T barbs to branch the flow, connect all your containers the reservoir.
The cool thing about this design is that, since the shut-off valves in the containers will make sure they won't just keep filling, the reservoir is simply topping off the containers when the water level drops, meaning that, no matter how many containers you have or how big they are, the size of the reservoir doesn't matter, you simply have to keep it full.
To show it in action, here's a picture of my girlfriend filling up the reservoir for our three containers with ease and aplomb, out of our bedroom window. Now isn't that easier than keeping track of the water levels of multiple containers and having to lug multiple buckets of water out of a window to fill them up?
I will update this instructable when our veggies start blooming.