A friend took the attached picture a few months ago. It is an Aloe vera potted in rice, coffee and sugar. I would like to learn how to use rice (and coffee and sugar) to grow plants in.
I wonder if such a growth medium has the advantage of being a passive dehumidifier?
The aloe is not growing in that medium. Sugar dissolves, rice and coffee decompose, when exposed to the conditions required for a healthy root zone. They would sour and kill the plant roots. Not suitable at all for growing plants in. It's either temporary, or someone doesn't know what they're doing, or the plant is in an inside pot.
What you could do, if you like that look, is to place a waterproof container with a smaller diameter inside the glass pot, before putting down the layers. When you add the layers of material, you will bury the inside container, up to the brim. This container can be used as a liner for the plant's pot (which should be a close fit). You would remove the pot from the display for watering, and return it when the drainage holes are not drizzling water.
In a Mexican restaurant at S. Cooper on Park Row in Arlington, Texas I have seen aloe vera maintained for the past seven months without water in a glass vase filled with uncooked rice and a light sprinkling of cinnamon (for decoration?). Supposedly, the rice absorbs humidity which supplies all required moisture. The plant is not increasing in size.
