New "Easy Roll" Worm Bin!

Build a 5 gallon self watering earthbox (Part I)

For those not familiar with the earthbox concept of a “grow box,” the original can be found at this link. You might want to familiarize yourself with the concepts and operation before proceeding. In a nutshell, the advantages to the earthbox (in order of priority) are:

  • A self watering system whereby moisture is provided to the plant roots consistenly via wicking from the reservoir underneath. Underneath air flow will also be encouraged to the roots as oxygenation is very important to plant growth and health!
  • A self fertilizing system whereby a strip of fertilizer slowly disolves and is pulled downward to the roots via diffusion. The buildup of salts over time is easily removed when the strip is replaced.
  • A stable planting medium which is covered via a plastic mulch so that evaporation is controlled and harmful organisms and insects are protected from the root system.
  • Though not unique to just the earthbox, a container approach allows the plants to be moved or protected from weather extremes.

Once the unit is setup, the maintenance and hassle are greatly minimized with such a system. I have done much research on alternative DIY plans and have come up with my own innovation which I think is a very cheap and effective plan utilizing the commonly available 4 or 5 gallon buckets.  I decided to break this project into two different parts so as not to be overwhelming.  I have drawn a quick sketch of the basic unit so that you can follow along with the steps and concepts more easily.

2buckets.jpgThe project requires two buckets, but with a little searching around, you should be able to readily find these from a bakery, painters, contractors, etc. I went to my local Walmart superstore bakery and they gave me 5 containers in which icing had been packaged (pictured on left). Referring to the sketch, our next step will be acquire a suitable container to hold the wick. In my case, I found a Campbell’s soup container to be the ideal size, and it will raise the water reservoir to accomodate about 1.8 gallons. I should also add that an alternative design could be accomplished by placing one bucket inside another (with the bottom as the water reservoir). However, it would require far more potting mix, water might not wick to the greater height efficiently, and you would compromise oxygenation to the roots.

markcutoff.jpgIn order to cut the exact height of the bottom screen section, simply take a marker and place on the wick container and then rotate the bucket all the way around.  We will eventually cut out a hole to accomodate this soup can “wick container” and it will fit down inside at the perfect height etc.

startcut.jpgAfter the height mark has been made all the way around, we can then take a suitable hand saw (hack saw etc), and start a cut on the line whereby we can then insert a jig saw. We will try to keep this cut even (in the next step), but if we get a little off we can even the cut out with a rasp or hand plane later. One way we can do this is to place this cutoff section on a flat sold surface. Then you can mark any areas that touch and trim them a bit etc.

jigsawcut.jpgNext we insert the blade of the jigsaw (any blade will do) into the cut that we made and start carefully cutting all around the container. Try to stay on the line so the the cut is even because this cut will form the bottom edge of the water reservoir section. If it is too uneven, the potting mix particles will be able to infiltrate into this area.  However, we can even the cut out as described in the preceding paragraph.

reliefcuts.jpgBecause the slant of the cutoff section will be opposite to the slant of the container when we flip it upside down, the sections will try to bind and not allow it to go down all the way. In order to get around this, I took my jigsaw and made several “relief” cuts as pictured. This will allow the plastic to bend inwards a bit and go all the way down inside the main container. Another way to get around this is to simply draw and cut the original line at 1/2 the height as we originally did. The choice is yours, but making these relief cuts only took me about 1.5 minutes.

5gal-screen.jpgBefore lowering the cutoff section into the main container, I marked and cutout for the wick container. You can cut carefully with a jig saw or better yet, buy one of those inexpensive adjustable hole cutters that attach to a drill. As can be seen, I also have started drilling many holes for the separation screen. If I had it to do over again, I would drill these a little smaller – as I think I used 1/4″ and there might be some leakage of soil mix into the water reservoir. I also drilled 1/4″ holes into the bottom soup can so that water can get into the potting mix therein.

Well, that is it for now, and the next time we will: 1) Pull the bottom section back out and drill a hole for the water tube to be inserted. 2) Drill overflow holes for the water reservoir. 3) Cut out the middle of the container top – which will be used to hold down the plastic mulch on the top. 4) Fill the container up with potting mix, and.. 5) Place the plant, fertilizer, and mulch etc. I expect this entire project (not including the potting mix) to cost me..”next to nothing!” If you republish these plans, I only ask that you provide a link and reference to this post or site.

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