on 8/29/04 8:50 PM, Viateur wrote:
> From: [EMAIL PROTECTED] > Subject: [OGD] day length > > Charles (Ufford), > > You wrote : "If the plants you have are from areas where it is nearish to > the equator and to sea level, you may not have to worry as much about > changing daylength." > > What is the day length at the equator? I don't remember that from school; I could look it up, but then so could anyone else! ; ) It doesn't change very much over the seasons (at least that is the opinion of a person living up near the great white north), but as you go further north or south, there are much greater changes. Seasonal changes in day and night lengths are the least nearest the equator, so, plants may not be as reactive to light lengths as other conditions like moisture timing, cooling from seasonal rains, and/or changes in light levels from clouds being around at the time of rainfall. > What is the day length at sea level at the equator ? this was not a point I was trying to explain, and people who live near sea level near in the tropics probably know that the temperature to a good degree doesn't change that much over the seasons, notwithstanding temperature changes from times of rainfall, if you are near the equator and at sea level. on the other hand, there are a number of species found in tropical highlands that have cooler temps and depending on their microclimate may see more seasonal or daytime/nighttime temperature changes at higher elevations. so, daylength at sea level is a bit of a nonsense concern, more important is the change in temperatures near the equator at sea level > > You also wrote : "plants must be more receptive to temperature conditions > than daylight". > Could you provide published references for this assertion ? I try to make a point with this statement that species I have grown and heard others talk about trying to grow, have not reacted to changes in their daylight length, as long as they contributed a minimum amount of total light. brighter light for shorter periods, less light but longer length, but both staying the same length for each condition. so, if you figure the total amount of light falling on a plant for those different conditions and lumens more or less average out, and the light length stayed the same for each particular spot, then changes in daylength were not the important factor, but that they must be more reactive to changes in temperature or moisture, or any other list of cultural info. > > Thanks in advance for any clarification. > > Regards, > > Viateur sorry, I work in the 'growing' field as opposed to the academic field and don't spend any time looking up published data, and I have no need for such. If I spend too much time near our weather computer (hooked up to the internet and a possible source for this information) our boss gets edgy and we hurry back to work! I think it is reasonable to take weather station data and come up with logical conclusions. Wait, as memory now serves, the weather data I am most directly using as my points of reference came from the wonderful series of species cultural books by Charles and Margaret Baker, Pescatorea - Pleione, Timber Press, Inc. Both Charles and Margaret worked with meteorological data, if my memory also serves from the introduction in their book. They both used weather station data from station locations nearest the areas they and others thought were the most likely places the species came from. Looking through the data shows correlations between the points I made above. Charles is a frequent contributor to this forum, and may answer these points also. Also memory serves that basic geography and world agricultural and sociological texts used in various classes I took in high school and college state the same points. also notice the use of 'may affect' and 'must be more receptive' which states an opinion based on these references and observations of weather data read in the previously mentioned book, and applied to the species in my collection, and the observations of other species growers on their plants, and the original location of these species. One of these texts I also somewhat remember a text title that was something like 'world agricultural and .... economics', which in points described how agriculture and culture was affected by the geology, society and geography. I don't remember the exact name and it is in a box somewhere where there is too much dust (and I'm allergic to dust mites...) hope this helps a little, and maybe Charles will also supply information along these lines, charles thanks to those who helped explain why my paph malipoense probably dropped its flowers so quickly. they all agreed that it might favor cooler, wetter conditions, and as it was a first bloomer that I had moved closer to the window, where it got hotter and drier... -- Charles Ufford Calen the Border Collie CGC - now in Heaven Oriskany, NY USA IPA, Central NY and Southern Tier Orchid Societies [EMAIL PROTECTED] http://www.paphiopedilum.net Http://www.geocities.com/charlesufford
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