As a general rule, there may be some small fraction of organic fertilizers that is soluble, but they should probably be considered suspensions and not solutions. Plants absorb nutrients in ionic form. If you think of the cell walls as a chain link fence with you tossing BBs at the fence and the BBs passing through, you are imagining an ionic solution. If you imagine yourself tossing basketballs at the fence, you're imagining a suspension - until the larger organic molecules are broken down into elemental form so it can pass through cells' semi-permeable membranes. I'm not passing judgment on your choice of fertilizer, just outlining the difference between soluble/solution vs insoluble/suspension.

I don't use the mix over & over, I put it in beds that have something like the gritty mix in them already, and I don't recommend it, but from the perspective of structural stability, there is no reason you couldn't use it indefinitely, only replacing a portion of the organic fraction (bark) after drying and screening out the fines.

Al

I will let Al answer the question you put directly to him, but I wanted to comment on this statement:
I avoid using chemicals generally because of runoff and water contamination issues.

First, thank you for having an environmental conscience!

Unfortunately there isn't much, if any, difference between organic/synthetic nutrient sources and run off.

It's certainly true that if you water a plant with Miracle Grow that any run off water will contain that Miracle Grow, but the same is true of non soluble fish emulsion. Likewise even a solid material is going to run off with drainage water as it is chemically/biologically processed and the nutrients turned into soluble salts.

I, too, am concerned about the environmental pollution caused by the use of fertilizers, particularly on the water bodies. It's one of the reasons I prefer synthetic fertilizers in containers where I can match the ratio of nutrients as closely as possible to what plants actually use. Makes for less waste and less to run off into the water bodies. I live in Wisconsin which has a ton of water and phosphorus is high in the soil in most of the state. It's a major source of pollution in the water and I get sick everytime I see what was once a beautiful, healthy lake get surrounded by private homes with manicured lawns. It's not long after that the lake has the life choked out of it from eutrophication. Then the tax payers have to front the bill for machines to go in and routinely harvest the explosive weed growth so residents can swim/fish/boat/jet ski as well as pay for the continual restocking of desirable fish that can't sustain their numbers anymore.

Justaguy, I went to U of Wisconsin. I miss the midwest very much and Wisconsin in particular. What a beautiful state. I spent time in northern Wisconsin too, in Medford and Madeline Island which were uniquely wonderful.

I think I put my objection to chemical fertilizers narrowly and simplistically so I'll elaborate some. Organic fertilizer runoff is an issue too but overall chemical fertilizers are less environmentally friendly. First off they are made mainly from non-renewable sources including fossil fuels.

Not everyone is concerned and conscientious as you so chemical fertilizer is often over-applied resulting in damage to soil structure (not talking containers and gritty mix) . Continuous use can result in a buildup of toxins as arsenic, cadmium, and uranium and a change in soil PH.
Beneficial microbial ecosystems are upset and pest populations increase with chemical fertilizer use.

I live in a gated community and have no control over what is applied to my lawn and front yard. One day my cats went out briefly and returned very ill. I found out that fertilizer had just been applied to the lawn. No one is notified when the landscapers apply chemicals so I have since kept my cats in. Another reason I avoid chemicals of this nature.