Each pocket holds two or three quarts of mix, open to the air on both faces, so it dries out faster than anything else here: daily watering in summer, twice a day in a heatwave. Put the pockets on a drip line, or expect to lose plants.

They won’t feed anyone, and that isn’t the point. They put herbs, strawberries and cut lettuce within reach of the kitchen, on a wall that was growing nothing. A south wall can bake them; the sunniest spot isn’t always the right one.