its a slow release fertilizer. Works well for what it does. The small pellets are made of clay i think that will be visable for a few years

Not sure what the pellets are made of, but when you sprinkle them on, they are a solid color, and when used up, they are more translucent, or clear. I use them in addition to organic fertilizer pellets, but the organics are my first choice.

Chris

I like Dynamite (Home Depot). Basically the same thing, only the pellets are grey and not near as visually offensive as Osmocote.
Clay

I prefer dynamite also; they have 2 types--1 for evergreen foliar type plants and 1 for flowering/fruiting species. I like the one for flowering/fruiting species as it seems to boost root growth, which is important for what we want to do with our bonsai.

Osmocote is temperature controlled. The pores in the coating (which the little balls are made of) only "open" up enough to release the fertlizer within when temperatures are above the high 60s. The "Osmo" in the name refers to osmosis--the traveling of a solution through a membrane (very rough translation) That means there can be a tendency--on warmer spring days--for the fertilizer to "dump" its load all at once, especially when (soil surface)temperatures can rise rapidly above 70.

Be careful in application, don't lay down a thick layer of the stuff hoping to fuel growth. You may wind up getting an overdose in the soil. This can happen when leaves are opening in the spring--the plant isn't using the fertilizer until leaves fully open anyway--when temperatures can spike in late afternoon.

I have gotten plants (either from nurserys or bonsai dealers, I don't remember exactly) where repeated doses of osmocote left depleted globules so thick one couldn't see the soil.

Clay

Clay,

I've seen that too, especially with plants trucked in from further south. Osmocote is easy to use and cheaper than other fertilizers. Repeated applications over a number of years can build up quite a layer of this stuff.