I have a potting mix from a majestic palm that I'm attempting to reuse, it has some odd small green balls in it that are maybe one or two mm large, perfectly spherical and uniform. I opened one and it appeared to break like plastic and was hollow inside. What is this, a slow release fertilizer? Is it biodegradable or is this plastic ball going to be in the soil forever?
Thanks
It'll be, as you suggest, slow release fertiliser such as Polyon - these are coated with polymer, and it depends on the formulation of the polymer whether they eventually bio degrade, and how quickly they do so. Given I'm not sure which one's been used, its hard to say whether they will eventually degrade or whether they'll still be intact in a few years. You don't need to attempt to extract them for re-use of the potting medium, they won't cause any harm, though the potting medium might if the plant/s you grew in it had any diseases or infestations.
