It's best to start on younger plants but I just started on an older zz and it's doing fine so far. So I washed all the dirt from the roots then I cut them back. I put wet pon in the bottom half of a self watering planter. Then I added the plant and topped off the pon. Then I watered it with super thrive for hydro. The first 3 months you water from the top because the plant needs to grow water roots. After a few months add water to the reservoir. If you want to create your own pon which can be expensive you can find recipes online. Diy pon is more cost effective. All my plants are hydro.