You can get the information on GDD and how
they relate to insects from the extension service in MA.
Fran
In a message dated 1/4/2005 5:15:29 P.M. Eastern Standard Time,
Hamptongar@aol.com writes:
I think that instead of going by the
imprecise method of frost free dates and forsythia blooms etc.,
etc...gardeners should be learning how to use GDD's or grower degree
days. Most states, through their extension offices or land grand
college have published lists or are working on lists that cover
diseases, weed germination, insect emergence...all based on precise GDD
information
I took a look at the first Google site that came up with GDD.
I think I understood what it was saying and its relevance (ok, I did, but it
took a few moments to get my brain round the equation and I have dealt with it
before). However, it is/was geared to serious growers and
farmers/researchers - not the average homeowner. Rings around the moon,
moon phases and wooly caterpillars, the Farmers Almanac and bloom times have
been around for generations and are not going to go away soon. They were
also built on non-technical knowledge that has held true for many generations
of successful gardeners. Add to that, the GDD (online) is
only done on a regional site, so unless you have recorded your thermometer
reading everyday (max and min) you might not be able to gauge your own
GDD for a specific need - ie when to plant peas, potatoes or basil, or when
lace bugs, June bugs etc are due to visit. In some counties the GDD
will vary considerably from mountain slopes to urban areas - not to mention
the soil types and moisture retention.
So as a tool for academics, serious growers and farmers - it is a useful
tool. For writers it might be too - we can use them to forewarn bugs
etc. However, I doubt that the average urban backyard gardener would be
motivated to use it more than for a curiosity. I would be interested to
see how it correlates with forsythia, or when you cannot 'squeeze the water
out of the soil' etc. and when butterflies arrive.
Kate
Copsey Garden Writer Herbs, Historic Gardens Pittsburgh,
PA
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