Q.Why does my soil remain crumbly?
I’ve added manure, compost, topsoil, even mulch around plants to my garden area and yet the soil remains crumbly and does not retain moisture. How do I get a nice rich soil to have some moisture?
I guess I can answer that my soil would be sand (although not like beach sand). I've done all the improvements in the article you mentioned, i.e. compost, aged manure, grass clippings, etc. The only thing I haven't tried is peat or coir dust; so I will be doing that next.
I've also noticed where the weeds are it holds the moisture in better. Can I plant a ground cover between the plants in my garden? Thanks for your help
How would you characterize your soil - sand, silt, and clay? In order to improve it, you must first identify your soil type.
Here is an extension article that will tell you how to improve the water retention in your soil - you will also want to ensure your garden area is free of weeds.
http://www.extension.org/pages/61062/improving-water-retention-in-soil#.VWPHN0aGNps