Hannon Why is rain water different from hose. Here in Berkeley, we found that the domestic (hose) water comes at about pH 8.9-9.2 whereas rain is much more neutral. We know this has a big effect on cacti and probably on lots of other things. Paul Licht, Director Univ. California Botanical Garden 200 Centennial Drive Berkeley, CA 94720 (510)-643-8999 http://botanicalgarden.berkeley.edu/ On 10/26/2012 10:43 AM, Hannon wrote: > As Leo notes, a summer dormant (leafless) bulb having perennial roots, such > as various Massonia, Albuca and especially amaryllids, can utilize water > that comes along during dormancy, at least in theory. Are bulbs with roots > growing upward and extending above the bulb positioned to take advantage of > the first rains, or to obtain a little water from a summer shower? Perhaps > both? Plants without perennial roots (many corms, narcissus, etc.) are not > benefited by water they cannot absorb and may be harmed if conditions are > favorable to pathogens. The other main fear in watering off-season is > starting plants into growth before their time-- days too long, temps > overall too warm, etc. > > Cool night temps are critical for the growth of Mediterranean geophytes in > autumn through spring and during an otherwise hot or warm dry dormancy > the often nights remain cool also (<70F) . Warm and humid ambient > conditions during this period can be fatal for these plants with or without > any supplemental watering. Watering should not be performed to "cool the > roots" unless a plant is in growth. Storage location and insulation by soil > mix are the best protection from heat and dryness. > > California has the driest, hottest conditions on average than any of the > Med climate areas. South Africa's Western Cape, by contrast, receives scant > rainfall in summer: at least 0.5" ppt in any given month (Los Angeles = > four months with 0.0 or barely more ppt). I keep all my bulbs completely > dry over summer with a few exceptions for plants that keep some green > parts. We get over 100F about 10 days/year but night stay cool, usually in > the 60s night minimum all summer. > > In my experience there is a big difference between rainfall and water from > the hose. It is easy to overwater and kill plants by watering too > generously with the hose, even with good water, but an even greater amount > of rainwater at the same time of year will not harm the same plants. Does > anyone have an explanation for this discrepancy? > > Dylan Hannon > > On 25 October 2012 21:51, Leo A. Martin <leo@possi.org> wrote: > >> Some of us have watered our southern African bulbs during the summer on >> purpose or through carelessness and have not had problems. The Great >> Karroo areas can get some summer rain, which generally comes from the >> northeast but doesn't reach the south coast of Africa, in contrast to the >> winter rain, which generally comes from the southwest and doesn't reach >> too far inland. The Karroo area is in the overlap. >> >> I have noticed especially Albuca and Ornithogalum seem not to mind water >> when it's hot. Albuca clanwilliamgloria seedlings began sprouting here >> several weeks ago in a large container I left out all summer, exposed to >> some rain and a garden hose that didn't pay attention. >> >> But realize that some winter-growing plants may die if watered even once >> during hot weather. Lachenalia comes to mind. So if I were perfect I would >> not water most of my southern African, winter-growing, deciduous-rooted >> bulbs in the summer. >> >> The fleshy-rooted Amaryllidaceae are another situation. Their roots stay >> fleshy all year and, even during long warm summers, don't wither deep in >> the ground. These plants struggle in my care unless I manage to keep their >> roots alive during their long dormancy, especially first-year seedlings. >> >> Leo Martin >> Phoenix Arizona USA >> >> _______________________________________________ >> pbs mailing list >> pbs@lists.ibiblio.org >> http://pacificbulbsociety.org/list.php >> http://pacificbulbsociety.org/pbswiki/ >> > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >