I have been using homemade earth boxes to grow some of the new dwarf variety tomatoes with good results. Wanting to make some more, but reluctant to spend several hours constructing the reservoir and wicking systems, I had an idea.
I put two grow bags inside a plastic tote from a big box store and filled them with a bag (1 cu ft) of planting mix plus a few shovelfuls of compost to create the growing volume, and added water to the space between the bags and tote walls made the reservoir. The holes in the bags provided the wicking system. Total cost ~$7 plus the mix; assembly time ~12 minutes!
The picture also shows the PVC frame I will use to support the branches. Unfortunately the overcast day did not show the mix in the bags well. Each bag has a cross-section of 9"x8.25" when empty, but filling pushes them out to a cylindrical shape about 11" in diameter. I calculated that filling the bags to a height of 12" produces a volume of between 4 and 5 liquid gallons each (about the equivalent of a 5 to 7 gallon trade pot) and they could be filled another inch or two if needed. I haven't decided whether to provide a cover or not, but I'll report back in a couple of months on how this is working.
