Having said all that, I don’t really know if xerophytic bulbs really grow in well-drained media or if that’s just a poor man’s substitute for a desert. Maybe a hardpan clay on a slope makes more sense. The process, in arid and semi-arid climates, has nothing to do with water draining away from bulbs, and everything to do with water percolating down to the depth of the bulb. A Facebook friend had the presence of mind to dig into the sand in the Negev Desert this past April, while taking pictures of Iris mariae. The sand was damp not too far beneath the soil surface (from winter rains), and damp to a considerable depth. Eventually, because of gravity, the water in the sand will go deeper, probably out of the reach of the iris’s roots. Water is also more readily available to plant roots in sand, and even more so in gravel, than it is in clay; it takes less energy for roots to pull water from the larger pore spaces. Clay, in arid and semi-arid climates, is much more difficult to wet. It would take days of rain for water to penetrate the soil here (a clay subsoil spread over the native sandy loam) to a depth useful for plant roots (except cactus). Yes, clay soil does hold more water than sand or gravel, but only if sufficiently wetted; most of the water is lost to evaporation before it can percolate to any depth. So the junos in the raised bed of clay here only get sufficient moisture from melting snow in the spring. The tops of the bulbs are about six inches (15 cm) deep. About one inch (2.5 cm) of rain has fallen on the garden here in the last month. It’s entirely possible that I’ll get the same amount of rain, one inch, from now until the end of the year. “Drainage” would be a disaster here. Rain needs to percolate down to the roots, not away from them. Bob Nold Denver, Colorado USA <HTML xmlns="http://www.w3.org/TR/REC-html40/" xmlns:v = "urn:///schemas-microsoft-com:vml/" xmlns:o = "urn:///schemas-microsoft-com:office:office/" xmlns:w = "urn:///schemas-microsoft-com:office:word/" xmlns:m = "http://schemas.microsoft.com/office/2004/12/omml/"><HEAD> <META content="text/html; charset=utf-8" http-equiv=Content-Type> <META name=Generator content="Microsoft Word 14 (filtered medium)"> <STYLE><!-- /* Font Definitions */ @font-face {font-family:///Calibri/; panose-1:2 15 5 2 2 2 4 3 2 4;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:///0in/; margin-bottom:.0001pt; font-size:///12.0pt; font-family:"Times New Roman","serif";} a:link, span.MsoHyperlink {mso-style-priority:99; color:///blue/; text-decoration:///underline/;} a:visited, span.MsoHyperlinkFollowed {mso-style-priority:99; color:///purple/; text-decoration:///underline/;} p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph {mso-style-priority:34; margin-top:///0in/; margin-right:///0in/; margin-bottom:///0in/; margin-left:.5in; margin-bottom:.0001pt; font-size:///12.0pt; font-family:"Times New Roman","serif";} span.EmailStyle18 {mso-style-type:///personal-reply/; font-family:"Calibri","sans-serif"; color:#1F497D;} .MsoChpDefault {mso-style-type:///export-only/; font-size:///10.0pt;} @page WordSection1 {size:///8.5in 11.0in; margin:///1.0in 1.0in 1.0in 1.0in;} div.WordSection1 {page:///WordSection1/;} /* List Definitions */ @list l0 {mso-list-id:///524900831/; mso-list-type:///hybrid/; mso-list-template-ids:///1681317558/ 67698703 67698713 67698715 67698703 67698713 67698715 67698703 67698713 67698715;} @list l0:///level1/ {mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l0:///level2/ {mso-level-number-format:///alpha-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l0:///level3/ {mso-level-number-format:///roman-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///right/; text-indent:-9.0pt;} @list l0:///level4/ {mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l0:///level5/ {mso-level-number-format:///alpha-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l0:///level6/ {mso-level-number-format:///roman-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///right/; text-indent:-9.0pt;} @list l0:///level7/ {mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l0:///level8/ {mso-level-number-format:///alpha-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l0:///level9/ {mso-level-number-format:///roman-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///right/; text-indent:-9.0pt;} @list l1 {mso-list-id:///1659188944/; mso-list-type:///hybrid/; mso-list-template-ids:-956923460 67698703 67698713 67698715 67698703 67698713 67698715 67698703 67698713 67698715;} @list l1:///level1/ {mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l1:///level2/ {mso-level-number-format:///alpha-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l1:///level3/ {mso-level-number-format:///roman-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///right/; text-indent:-9.0pt;} @list l1:///level4/ {mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l1:///level5/ {mso-level-number-format:///alpha-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l1:///level6/ {mso-level-number-format:///roman-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///right/; text-indent:-9.0pt;} @list l1:///level7/ {mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l1:///level8/ {mso-level-number-format:///alpha-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///left/; text-indent:-.25in;} @list l1:///level9/ {mso-level-number-format:///roman-lower/; mso-level-tab-stop:///none/; mso-level-number-position:///right/; text-indent:-9.0pt;} ol {margin-bottom:///0in/;} ul {margin-bottom:///0in/;} --></STYLE> </HEAD> <BODY lang=EN-US dir=ltr link=blue vLink=purple> <DIV dir=ltr> <DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000"> <DIV>Having said all that, I don’t really know if xerophytic bulbs really grow in well-drained media or if that’s just a poor man’s substitute for a desert. Maybe a hardpan clay on a slope makes more sense. </DIV> <DIV> </DIV> <DIV> </DIV> <DIV><FONT color=#000000>The process, in arid and semi-arid climates, has nothing to do with water draining away from bulbs, and everything to do with water percolating down to the depth of the bulb. </FONT></DIV> <DIV><FONT color=#000000>A Facebook friend had the presence of mind to dig into the sand in the Negev Desert this past April, while taking pictures of Iris mariae. The sand was damp not too far beneath the soil surface (from winter rains), and damp to a considerable depth. </FONT></DIV> <DIV><FONT color=#000000>Eventually, because of gravity, the water in the sand will go deeper, probably out of the reach of the iris’s roots. </FONT></DIV> <DIV><FONT color=#000000>Water is also more readily available to plant roots in sand, and even more so in gravel, than it is in clay; it takes less energy for roots to pull water from the larger pore spaces.</FONT></DIV> <DIV><FONT color=#000000></FONT> </DIV> <DIV><FONT color=#000000>Clay, in arid and semi-arid climates, is much more difficult to wet. It would take days of rain for water to penetrate the soil here (a clay subsoil spread over the native sandy loam) to a depth useful for plant roots (except cactus). Yes, clay soil does hold more water than sand or gravel, but only if sufficiently wetted; most of the water is lost to evaporation before it can percolate to any depth. </FONT></DIV> <DIV><FONT color=#000000>So the junos in the raised bed of clay here only get sufficient moisture from melting snow in the spring. The tops of the bulbs are about six inches (15 cm) deep. </FONT></DIV> <DIV><FONT color=#000000></FONT> </DIV> <DIV><FONT color=#000000>About one inch (2.5 cm) of rain has fallen on the garden here in the last month. It’s entirely possible that I’ll get the same amount of rain, one inch, from now until the end of the year. “Drainage” would be a disaster here. Rain needs to percolate down to the roots, not away from them. </FONT></DIV> <DIV> </DIV> <DIV>Bob Nold</DIV> <DIV>Denver, Colorado USA</DIV></DIV></DIV></BODY></HTML> _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/…