Hi Jim

> That's not what the extensive experience of greenhouse growers
> as a group shows.  Plants grow in a cumlative stepwise manner,
> so if the average temperature for the day (the sum of the daily
> high and low, divided by 2) is greater than 55
> degrees,

What concerns me is the simplicity of this averaging...

Taking 12 deg C as the trigger point, I can have a day with a low
of 5 deg that occurs for 21 hours out of 24 and a high of 20 deg
that occurs for 3 hrs or I could have a snap frost of 0 deg for
an hour with 25 deg for the rest of the day, both give an average
of 12.5, but I seriously doubt that the growth would be the same
under the two different conditions.

While the figures I have chosen are extreme and would vary in a
smooth periodic way, they are not beyond the bounds of
possibility.

 Best Regards & 73s, Dave Cushman... G8MZY
Beekeeping & Bee Breeding Website
Email: [log in to unmask] or  [log in to unmask]
http://website.lineone.net/~dave.cushman &
http://www.dave-cushman.net

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