In the foreground and the background are two ways agricultural scientists are trying to conserve growing space for small plants. Depending on the plant you can at least double the square footage output of a food crop using the A-frame in the background. But look in the foreground how many plants you can grow if you tier them with drip irrigation. Literally the sky is the limit. Here it looks like they are able to grow 36 plants in the space it would take you and me to grow one. With some PVC pipe, some drip hose, plant food and, oh, say lettuce, you could do this at home.