materials: rubbermaid tub; 1/2" pvc pipe approx 18" - 24" long; six plastic flower pots (the kind your plants come in when you buy them) of the same size, dremel or small saw or big scissors, dirt, water, nail or drill, plastic garbage bag, granular fertilizer.
Step 1: Step 1
an earth box is basically a big tub with a water reservoir in the bottom. i used a BIG rubbermaid tub i bought on clearance in january for next to nuthin' at walmart. you'll need six pots or so, the plastic kind plants come in when you buy them, to be the support under the floor of the box. take the lid and trace around the mouth of the pots on opposite diagonal corners. also make a small circle the circumference of the pvc pipe.
Step 2: Step 2
cut out these holes. ALSO, around the inner rim of the lid, cut the lid out so the rail that clips onto the edge of the box remains intact. the center of the lid will act as the floor of the box, resting on top of the pots, holding the dirt. place the center of the lid inside the box on top of the pots. arrange the pots so two of them are situated underneath the large holes. this is also a good time to punch or drill holes in the side, level with the "floor," for drainage. i did approx four holes per side.
Step 3: Step 3
insert pvc pipe! best if it's angled. now time to fill the tub with dirt. first top off the pots that are visible with dirt. these will wic water from the reservoir up into the rest of the tub. continue to fill with dirt, watering it down as you go along so it settles, and fill it TO THE TOP. this is the only time you will water the dirt directly. the rest of the time you will use the pvc pipe to fill the reservoir with water. scoop a shallow trough lengthwise out of the dirt and fill with dry, granular, fertilizer. take your plastic (garbage bag, or landscaping plastic) and cut a rectangle about three inches longer and wider than the top of the tub. lay it over the top of the tub and use the rim of the lid to clip down and hold it in place. you will not remove the plastic again. you cut holes in the plastic to plant your seeds/plants and voila! you done it!