Time release fertilizer in direct contact with roots

[SouthPark]

Fertiliser is food of sorts ...... as in 'vitamins'/elements ..... essential elements. I have Angraecum eburneum plants growing outside in orchid pots - scoria media - that haven't been repotted for a few decades, and never received any man-made fertiliser at all.

The roots have actually grown out of their pots though, and some are touching the ground - the soil. And some insects etc are living inside the pots (in the scoria). So they likely get their elements/vitamins from the ground and/or the activity in the pot. These orchids are just beginning to form flower buds on their spikes for this latest round of flowering.

Nearby are relatively big dendrobium (hard cane) ones ------ also growing in scoria media, never been manually fertilised as well for a few decades. They flower very reliably too. These orchids just get their water from either the air or from the automatic lawn sprinkler that waters the lawn (and these orchids along with it at the same time) each night.

As for 'time-release' fertiliser, as long as it gets the job done without ever harming a plant, then that'll be great. The other thing thing is sharing the information about this sort or variety of fertilising method. Great to know what has been workable for others out there.