Three years ago I set up an experiment to measure the effect of snow cover, but unfortunately winter that year was a total non-event, and so I discovered nothing. But what I did was this (with the help of a meteorologist friend): I dug a pit in undisturbed soil and inserted temperature probes at three depths (don't recall exactly, but probably 12", 6", and 2"), and perched a fourth just above the soil. The pit was then filled and watered heavily to settle the soil. A pole holding a yardstick (for measuring snow depth), a hi-lo thermometer (for air temps), and connectors for the probes was erected at the same site. The idea was to go out each morning and measure soil temps at all 4 depths, the high and low temps for the last 24 hours, and the snow depth. This would all have worked beautifully, except that nothing of meteorological interest happened from November through January (when I gave up taking readings) or at any point thereafter. The idea was good, however, and I hope to try again this winter (the last two have been quite interesting winters). Jim is right to suspect that soil temps tend to stay pretty balmy under a lot of snow. After our 5' snowfall this winter, when I dug pits in front of the greenhouses so I could open the doors (this meant I literally dug a pit, hopped down into it, and continued digging until the door could be freed), the soil underneath was not frozen. I've long suspected that it rarely freezes more than 2-3" down. Hence the experiment, which really should be repeated. Ellen Seneca Hill Perennials Oswego NY USA Zone 5 Original Message: ----------------- From: Jim McKenney jimmckenney@starpower.net Date: Fri, 16 Jul 2004 13:23:15 -0400 To: pbs@lists.ibiblio.org Subject: snow cover; was: Re: [pbs] pushing envelopes At 07:06 PM 6/26/2004 -0400, Ellen Hornig wrote: >We have excellent snow cover, and this is no doubt part of the explanation. I envy Ellen's snow cover. Here, several hundred miles south of Ellen, where the winters are ostensibly milder, many of the plants she mentions are not reliable in the open garden. Eucomis, Galtonia, Crocosmia, many Kniphofia and others simply don't survive bad winters. Snow cover here is brief and erratic. Years ago I had a conversation with a Canadian agriculturist who assured me that cold as the air might be, down under the snow cover the temperature was close to 32 degrees F. It's hard to believe, but Ellen's success in an area with snow cover seems to support this view. Jim McKenney jimmckenney@starpower.net Montgomery County, Maryland, USA, USDA zone 7, where we don't have reliable snow cover, but we sure do have lots of mulch. > _______________________________________________ pbs mailing list pbs@lists.ibiblio.org http://www.pacificbulbsociety.org/list.php -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ .