The problem is capillary action holding water in the fine spaces in the medium. Until the hydrostatic pressure of the vertical column of water exceeds the capillary attraction/surface tension of the water at the bottom of the medium, the water won't flow down and out. You will always get a better draining bed when the medium is uniform from top to bottom. In addition, the taller the water column, the better the top of the bed will be drained. It's physical chemistry or physics at its finest. Jim Shields At 08:40 AM 12/4/2013, you wrote: >Agreed that if the thought is that crocking results in better drainage - >well, that's a crock of animal fertilizer. >... >Bulb in 6 inch wide container, with 1/3 of 12 inch height filled with >soda cans / packing chips (ghost farts, my brother calls them) / >whatever should still drain satisfactorily, wouldn't it?. > >Judy in New Jersey ... ************************************************* Jim Shields USDA Zone 5 P.O. Box 92 WWW: http://www.shieldsgardens.com/ Westfield, Indiana 46074, USA Lat. 40° 02.8' N, Long. 086° 06.6' W