The EarthBox is a pot gardening system available commercially throughout the country http://www.earthbox.com/ . The EarthBox is somewhat expensive but more than worth the investment for those who have limited space or who may be required to do most their gardening on an open or even enclosed back porch. During the winter in Florida I do nearly all of my gardening in pots and EarthBoxes on an enclosed lanai (screened in back porch, mostly open to the elements). I have three EarthBoxes and will likely purchase a fourth next year. They cost about $50 each and come with a variety of basic elements at no extra cost. However, there are a number of other attachments for which you will pay extra. I won’t try to talk about all of the options which you can investigate at the Website or in the showroom of a local reseller. These are such items as conveniently attached trellises whereas in most cases you can rig your own. Further, you can in some cases adapt your own large pots or even in some cases smaller pots to an EarthBox-like concept and get better yields of whatever you plant before such an adaptation. In other words, once you see the commercial EarthBox at work for you, it gives you an opportunity to do your patio gardening in pots with greater efficiency. Thus, my overall investment in Earthboxes has paid off.
The Earthbox is, in fact basically a box 23 by 12 inches wide at the top and 10 inches deep. At about about one and one-half inches from the bottom several indentations accommodate a tight fitting plastic narrow mesh screen with openings of a little over an inch square at the two adjacent ends (corners) of the 23 inch wide front side of the plastic screen. This screen can be fitted directly into the bottom of the EarthBox about one and one-half inches from the bottom. Into one of the open squares you can place a one and one-quarter inch diameter, one foot long black plastic tube which slips neatly into the open right-side square of the plastic narrow mesh screen already fitted into the EarthBox. Looking at the center of the Earthbox on the front side you will see an inch or so indented region at the bottom. The long black plastic tube just fitted inside the box should appear in the right-front corner of the box. When everything is ready and assembled you will add water (usually from a hose) directly into the bottom of the box through the the black plastic tube. When the water level at the bottom of the box reaches the bottom of the narrow mesh screen it will start to overflow through a hole at the top of this central indented region in front of the box. You will see the water coming out and immediately stop adding water with the hose.The bottom of the EarthBox has been filled with water–all further additions will overflow out of the box.
Next you add soil to the box, but first you add it and pack it down at the second small square opening in the bottom of the box–this is the square opening in the right front part of the box. Care is taken not to add too much soil loosely as it will just spread through the entire bottom of the box. Pack it down a bit hard, but don’t push it. This soil is extended only sparingly into the volume where the water will be–and acts as a wick to bring water up to where the plants are. After the wick is prepared I add the remainder of the soil and fill up the box to a depth of about one-inch or so from the top of the box. I just use a bag of Miracle Grow amended soil, about $5-6 at a local vender. Those who sell EarthBoxes recommend other procedures and I have used them, but now after several years of planting in EarthBoxes I find the approach I use to be easier and more convenient.
You are now ready to plant. In one of my EarthBoxes I plant two cherry tomato plants–each about six inches from each end through holes made in a plastic covering on top of the EarthBox. I place a tomato trellis over each tomato. I place two wooden stakes into the soil in the middle and use a little wire to connect each stake to each trellis to stabilize and interconnect the trellises. In the middle between the tomato plants I place a bead of fertilizer in a line perpendicular to the line between the plants. I often add a little more over the season. As the plants grow and fruit appears the water demands increase markedly, and I water through the open plastic sleeve far more often than at the beginning.
As the season progresses plant roots grow downward toward the water and water rises from the bottom reservoir toward the top and moves through the added fertilizer and dissolve some of it moving it toward the tomato plant roots. Water then moves into the plants. Yields of tomatoes and appearance of the plants are usually between impressive to fantastic.
In the other two EarthBoxes I plant pole beans and snowpeas. The pole beans generally do exceptionally well. The snow peas often do much better than they would in other pots or in the field but not as well as I would think based on watching the effect of EarthBoxes on pole beans and tomatoes. Next year I’m going to try cucumbers which I have never had much luck with growing them up trellises in regular large pots.
Having watched the EarthBoxes at work for a few years now, I’ve slowly tried to adapt the concept to smaller, regular pots. I get some wire or plastic mesh screening and cut out two holes across one another–one for the soil wick, the other for the plastic sleeve. I add soil in one hole and a plastic sleeve–usually a cut piece of old, no longer used garden hose to the other. Underneath the mesh screen I usually place a few larger rocks that have been well weathered or pieces of old garden pots. This is to stabilize the mesh screen and is not intended to fill up all the space that should be available to added water. Then soil is added, something is planted and the stem and soil covered with plastic which is wired down around the edges and often stabilized at soil level with a few rocks. Later in the season the covering is temporarily adjusted as more fertilizer is added.
After 2 years the soil in EarthBoxes and in pots modified as EarthBox like, is changed. I add all of the used soil to a low region on the property which I will work one later using the Fukuoka straw-green manure methods to regenerate it’s potency. Straw, green manure and further mulching can work to improve the growth of vegetables in pots but I’ve never tried it in EarthBoxes. I’m thinking that’s something I should work on next growing season.