Roof-top pool gardens: fill a wading pool with vermiculite or gravel to 2 to 4 inches and top with soil mixture. Then drill
via: blog.oregonlive.com
Roof-top pool gardens: fill a wading pool with vermiculite or gravel to 2 to 4 inches and top with soil mixture. Then drill holes through the sides where the vermiculite ends and soil starts. Water is added to the point it begins to just trickle out the holes. Roots reach down and suck up the water. The technique takes less water, time and equipment than overhead or drip irrigation.