Capillary theory teaches that this simply leads to a "perched" water table in the container. The USGA has done extensive research on the physics of this on putting greens. "The layering of a finer textured and single grained soil material over a coarser textured media results in the formation of a zone of saturated soil above the interface. This is shown in the figure below. A necessary condition for this occurrence is a distinct interface between these two porous media as would occur in a USGA green adhering to the bridging criteria for the gravel. As we shall see later, this zone of saturated soil is not a true water table since it lacks a free-water surface (i.e. a depth within the profile where soil water suction equals zero). The soil is saturated nonetheless, because the soil water suctions that exist in this zone do not exceed the air-entry value for the root zone. " It's time to put this practice to bed. Mark Mazer Hertford, North Carolina USDA 8a On Tue, Dec 3, 2013 at 1:10 PM, Judy Glattstein <jgglatt@gmail.com> wrote: > Ina, when I used to teach container gardening classes we'd often be > discussing those large wooden half whiskey barrel containers. My > suggestion was to use aluminum soda containers, opening side down. One > or even two layers, with second layer - if any - offset from the lower > layer. Then cover the cans with water permeable non-woven landscape > fabric. Cut somewhat oversize, so that the fabric can be brought up > against the side of the container for a few inches. > > Judy in sunny New Jersey where we've gone from night temperatures in the > teens Fahrenheit into another heat wave. High 50s Fahrenheit predicted > for today and the next two. Very peculiar weather this year. > > --- > This email is free from viruses and malware because avast! Antivirus > protection is active. > http://www.avast.com/ > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >