Drop two handfuls of stones into the jar. The rattle should be rare and illicit. Scatter charcoal over them, then pile on the soil. Sink your hands into the soft, speckled earth and leave them there a while if you like the feeling. Create a hollow in the centre; this can be done as an excavation, as if gravedigging, or with a swirling motion, as if selecting a dessert from the cake trolley. Place the plants on top (gently!) and cover the roots. Seal the jar and place it in sunlight. Never open it again, even in times of emergency.