Most nursery pots I see, whether in big box stores, or small town garden centers, have that slow release fertilizer piled on top of the container soil. It looks like small green balls, and there seems to be plenty of it in the containers. I asked a nursery owner once what it was, and they said slow release fertilizer. I've never seen it for sale though. Anybody know exactly what it is? I'm sure these big nurseries buy it by the ton.

Probably Scotts Osmocote.

Not sure what the stuff they use is, but Osmocote is a brand of slow release fertilizer, which has several types, some more for growth, some for flowering. Don't remember green ones, but I don't use it much - only the indoor plants.

It does look like Osmocote, although the stuff I use is light n color.

Yeah, probably something like that. The fertilizer I'm talking about is dark green in color, and probably not a brand name. Very common in this area. Looks like the green stuff in the middle, and I suspect heavy in nitrogen.

Just bought a 50lb bag of it.

https://www.amleo.com/osmocote-19-5-8-s ... er/p/1958/