Just posting a link to what exactly is in the Care Kit because I'm curious about all the bits and pieces myself. I think the soil amendment may be water holding crystals, and I don't think you would want that....if that is what it is.
Edit: Nope. I was wrong. " Derived from naturally occurring active carbon peat humus RETAIN is intended to be applied at the transplant stage, or in topdress applications. RETAIN provides carbon to feed soil biology, help hold nutrients in the root zone and increases cation exchange capacity."
Tropical Fruit Care Kit