Balcony / container gardening can be made very easy by having self-watering containers. These are containers that have water reservoirs in the bottom, and save you the time from checking your soil every two days.
To make the containers that I have made, you will need the following supplies:
- 1 large rubbermaid tub
- 1 1-inch PVC pipe (should measure 1 inch taller than your rubbermaid tub)
- 5 3-4 inch PVC pipes measuring 6-inches high (usually you will buy one long one and cut it down to 6-inch pieces)
- 22 zip-ties
You will also need the following tools:
- 1 drill w/ drill bits
- 1 jigsaw (or other saw suitable to these needs)
- 1 permanent marker (I find a black Sharpie works best)
DIRECTIONS – THE RESERVOIR TUBES
The reservoir tubes are the five tubes that sit at the bottom of the tub. Two (or more if you wish) will be filled with soil, the other three will be left unfilled and act as supports for your soil landing.
Cut each tube to be approximately 6 inches (or 1/3 of the size of the tub).
Drill four holes at the tops of each of the tubes, at even distance from each other. These holes need to be big enough to fit a zip-tie through. Drill many holes in the tubes; this is to allow water flow through the support tubes, and to allow the soil to wick the water up from the bottom.
DIRECTIONS – THE FILL TUBE
Make sure the fill tube is cut to approximately 1-inch higher than the tub.
Drill three holes, vertically, at the bottom of the fill tube – this helps keep the water from getting backed up when filling the container.
DIRECTIONS – THE SOIL LANDING
The soil landing is the insert that sits inside the tub, and the most amount of work in terms of planning.
1. Cut around the outside of the lid, so that it will fit inside the tub. Keep in mind that the tub will probably taper towards the bottom – use this to your advantage, and leave some of the part of the lid that warps upward. This will keep gaps from creating around the outside of the tub. Try to cut the lid so that it fits well around any weird shapes in the tub.
2. Trace five circles, the same size as the reservoir tubes. Trace both the inside and the outside of the tubes, and place these traces as follows: one by each corner, and one in the middle. If your tub is particularly large, you may want to add a sixth tube, spacing them three on each side.
3. Trace and cut a circle the same size as the fill tube, at the end (as close as possible to the end without breaking the rubber lid).
4. Cut two of the five circles (or three of six, if you have a larger tub), preferably opposite sides from one another. DO NOT CUT ALL OF THE CIRCLES!
5. Mark and drill four holes around the outside of the circles you have just cut. Mark and drill four holes around the INSIDE AND OUTSIDE of the circles that you drew but didn’t cut. These smaller holes are where you will attach the reservoir tubes with the zip-ties.
PUTTING IT ALL TOGETHER:
(This is the fun part. You’re almost done!)
1. Attach all of the reservoir tubes to the bottom of the soil landing. I find the best way is to insert the zip-tie, top-down, into the inside hole, and then circle it around to come up through the outside hole. Do this loosely, because if you make the zip ties too tight right away it is very difficult to work with the other tubes.
2. Once all of the reservoir tubes are attached, tighten all of the zip-ties and clip the ends. When tightening the zip-ties, it’s best to have the hook from the zip-tie flat against the lid.
3. Slide the fill tube into the hole you previously cut for it, with the three holes at the bottom (with the reservoir tubes).
4. Set the whole unit down NEXT TO the tub, and mark and drill 2 holes in the tub itself. One hole should be slightly lower than the other. This is for water overflow, in case you fill your earthbox too full. It will save you from accidentally soaking your soil.
5. Set the whole unit INTO the tub, and attach the fill tube to the side of the tub with zip-ties. Mine took two zip-ties because they weren’t very long. Most rubbermaid tubs have small holes already in the handles – if yours doesn’t, go ahead and drill them.
6. Fill the two “empty” reservoir tubes with soil and pack it down. This is what will wick the water up to the top.
7. Fill the rest of the earthbox with soil.
8. Fill the water reservoir using the fill tube. The first time you do this, you will want to watch the overflow holes. After you fill it, I suggest you find a long wooden stick and mark where the water line is. This will make your life easier in the future when you need to find out how much water remains in the reservoir.
Voila! You now have a self-watering container for your plants! The most beautiful thing about these (especially the size I made) is that you can pretty much go 2-3 weeks before you have to water them again.
As far as replenishing the soil goes, I add new soil each year and remove some of it, mixing it well. I also use a heavy dose of Miracle Grow once a month, directly into the water supply, to help nourish the soil throughout the summer.