For the last two years, I had been using some Home-made Earth Boxes to grow some of the new dwarf tomato varieties with good results. Wanting to add some more, but reluctant to spend the several hours it took to create the necessary reservoir and wicking system, I thought of another possible way to do it.
I took two 5-gallon plastic grow bags and put them in a plastic tote box from the a big box store
(total cost ~$7), filled them with a 1 cubic foot bag of planting mix plus a couple of shovels of compost, and voila, a self-watering system with minimum assembly. Just pouring water into the space between the bags and the tote supplies the reservoir, and the holes in the sides and bottoms of the grow bags provide the wicking.
While the bag cross-section forms a 9"x8.25" rectangle when empty, filling them rounds them out to a rough cylinder of about 11" diameter. I calculated that filling them to a height of 12" produces a total volume between 4 and 5 liquid gallons, which is equivalent to a 5-7 trade gallon container. Since many gardeners have reported growing tomatoes in 5-gallon containers (they never say whether this is liquid or trade gallons) I thought that this should be plenty for my dwarf tomatoes. (The bags can be filled another inch or two if more planting mix is needed.)
The picture shows the filled bags in the tote with a PVC cage which will be placed around it to support the branches. I haven't decided whether I'll add a top (for another $ or two) or not, but I'll report back in a couple of months to let you know how this works out.
