My understanding about why organics are not effective in pots is that it has nothing to do with them "washing out." Organic fertilizers need to be broken down by microbes before they are in a form that can be used by plants. And in containers, populations of the necessary microbes can be much less stable than in the ground, for a variety of reasons. So.. substituting slow release versions of organic fertilizers really doesn't address the problem in any way.

Thank you!

Amanda, I have tried osmocote in pots and it really seem to work well.