Some weeks ago, I got some seedlings of Argania spinosa and a palm tree growing in my garden. I transplanted them in a plastic bottle to study the possibilities to grow them with a minimum of water.
The potting mix in the plastic bottle was treated with 5 g of the soil conditioner TerraCottem per liter of soil. The water stocking polymers of the TerraCottem reduce the irrigation needs by 50 %.
Seemingly the 3 seedlings are doing very well.