Earth box!

Life got hectic for a while -- honestly, it still is. But this is a nice way to forget about my upcoming tests and assignments due. (Hey, at least I cleaned the bathrooms in my apartment this weekend...)

About a month ago, I was on instructables.com (I love that website) where I found instructions on how to make my own Earth Box. I had never heard of such a thing, and after reading about it, and doing more research online, I thought it'd be a great idea to make one! Of course, I took pictures throughout the whole process.

First, I went to Wal-mart where I picked up a cheap pond basket, potting mix, and an inexpensive "rubbermaid" container (actual Sterilite) before heading over to Home Depot to get a length of PVC piping.

My new Dremel tool really came in handy with this project. The first thing that I did was cut out the center part of the lid. In this cut section, I cut out a square a bit smaller than the size of the pond basket in the center, and a circle about the diameter of the PVC pipe that I had in the corner.

I had to trim the edges of this cut section so that when the basket was attached, it would sit inside of the tub perfectly -- it was a lot of trial and error work, and unfortunately, I didn't take any measurements throughout this whole project.

I then took 4 equal lengths of PVC pipe to use as supports for the cut section. Trying to get these to the right size was also time consuming due to my trial and error methodology. To use these, I used hot glue to glue them to the bottom of the tub in places which would give the cut section the most support from the weight of the soil to be on top. Because of the pipe which was going to be coming through that hole I cut out in the cut section, I had to shift one of the supports further down. Keep in mind that the shifted support is in a specific location -- I failed to realize this and had to rip out my support and glue it back down in a new position.

In the picture above, you can see the supports glued down in their respective areas. Notice the location of the shifted support -- this is the WRONG location. I really should have noticed that sooner.

The next step was to glue the pond basket to the cut section in another effort to support the weight of the soil (at least to keep the pond basket stabilized in the correct place). This was fairly easy and hot glue did the trick again.

I guess now would be as good a time as any to explain the concept behind the earth box. This is how I take it... With container gardening, one of the toughest things to keep on top of is watering. With such small space for the roots to grow and for soil to maintain moisture, water is used very quickly. This is especially true for clay/terracotta pots, which allow moisture to escape. The earthbox is a container with a built-in reservoir in the bottom. A portion of the soil is in direct contact with the water in this reservoir which allows the water to wick up into the soil to the plants' roots above. In this set up, the cut section separates the soil from the reservoir while the pond basket allows for the direct contact for part of the soil. The reservoir is filled and topped-up using a length of PVC piping which extends down through the soil, through the small hole in the cut section, and into the reservoir. This system ensures that plants will always have enough water since when the soil dries out either from evaporation or take-up by the plants, more water wicks up to replace it. To prevent flooding of the box, drainage holes are put at the top of the reservoir section, to make sure the water level doesn't extend beyond this point.



The next step was to insert the cut section with the attached basket into the tub to rest on the supports. No gluing is necessary here as it should fit well with the supports keeping the future load from bending the plastic.


The pipe to fill the reservoir needs to extend deep into the reservoir itself, in order to help determine when the reservoir needs to be refilled or topped-up. The pipe was cut at a slant so that water would always be free to flow from it (I hope that's relatively simple to comprehend why).


Here you can see my horrible job at cutting that angle in the pipe. But hey, it works.


After putting it all together (inserting the pipe), I filled the pond basket with moistened potting soil to which I had added a bit less than a 1:1 ratio of perlite. Hopefully, this would help the water wick up to the drier soil quicker to begin with. Whether it worked or not, I don't know...but it did make sure the soil was fairly compacted in the basket. Before filling the reservoir or putting more soil in, I went ahead and inserted the drainage holes I mentioned ealier. I put three each on the long sides and one on each shorter end at roughly the same height...just to make sure that it'll drain quickly if there is an overflow.

I filled the tub the rest of the way up with soil, and put a couple of gallons of water into the reservoir (filled it until it started running out of the drainage holes).

I helped the water to equilibrate in the soil by watering from above a bit, to allow cohesion to help get the rest of the water to come up from the reservoir.

My first subject to be put into the earth box, I chose, was going to be the tomato seedling that I had started a couple of weeks back. I dug a hole for it, placed it in the corner of the earth box, and then laid a sheet of white plastic [read: trash bag] over top with a slit cut for the seedling.

The concept behind the plastic sheet is it prevents water problems in two ways. One, it prevents water from evaporating from the surface of the soil. This keeps as much moisture as possible in the soil and lessens the possibility of any part of the soil drying out. And two, it prevents rain water from infiltrating into the soil which could drown the plants if the drainage holes aren't performing well.

This picture above was taken right after it rained and if you can see, there are small puddles of water where there are indentations in the soil. This caused pools of water to form. This was one of the reasons I decided to later remove the plastic.

I removed the plastic a couple weeks later as it was just a hassle and not providing much benefit that I could tell. I decided that in order to retain the moisture, I would plant a dense ground-cover plant which would use water, yes, but prevent soil erosion and have a net moisture retention effect. I chose Corsican mint (also because it smells AMAZING). So I removed the plastic, divided my corsican mint into three sections, and also planted a Stevia plant I had bought at the farmers market along with the mint.

Here to the right is what the system looks like as of this morning. You can see the tomato plant has gotten much larger. The stevia got knocked over a little bit with the past storm so it's leaning a bit towards the corner more than it did originally, and you can see clearly one of the sections of corsican mint. I'm hoping the mint will cover the entire surface before too long (it's already on its way). As it is, I've only had to top-up the reservoir once. This system is performing rather well, I think.

Any questions, ask me in the comments!