wrote in message
ups.com...
What we need is a device that illuminates a plant or tree to the
degree in which it receives an amount of water. For example, as
the plant or tree is being watered, the outside surface of the tree
will 'glow' with a purple phosphorus as the water level within the
plant's roots rises. When sufficient water has been given to the
plant, the entire plant itself will then glow with an amber phosphorus
-- indicating enough water has been given.

How to make the plant or tree glow, however, is open to debate.

Paul


Plants become flaccid and droop when they run out of water.
Therefore all that is needed is a device such as a strain gauge to determine
the degree of stiffness and erection at any point in time.
This could be connected to an automatic watering device to activate a
watering system on the first sign of flaccidity.

Alternatively one could insert a conductivity meter into the soil next to
the plant's roots which would measure the conductivity for different water
levels.