The norcal blend is like 25% worm castings I believe, and the castings themselves are hydrophobic at least when slightly dry. This and some of the other materials make it hard to wet without a wetting agent. I prefer not to use a wetting agent because I believe it will cause its own issues eventually. Even after multiple waterings with drip irrigation you could find dry areas. I'd say you almost have to use a wetting agent with this soil or water it over 2-3 months to get it ready.