Plant watering

[K N and P J Harris]

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> bionet/plants #57, from c.stevenson at qub.ac.uk, 932 chars, Fri  12 Jan 
1996 19:16:47
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> Article: 8568 of bionet.plants
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> From: c.stevenson at qub.ac.uk (Peter S)
> Newsgroups: bionet.plants
> Subject: Plant watering
> Date: Fri, 12 Jan 1996 19:16:47
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> To all you green fingered people, 
> 
> I was wondering if any of you know any methods, or where I can see/buy 
a 
> device which will automatically water a plant as it needs it.
> This would aid me greatly in my GCSE technolgy project, so if any of 
you could 
> help me out it would be GREATLY appriecated.
> 
> Thanks
>   Peter Stevenson
> 
> --------
> Mail to: c.stevenson at qub.ac.uk
There are devices which assess the drying out of the atmosphere by the 
change in resistance of a device which relates electrical conductivity 
to moisture. This then sets off a relay which activates a pump which 
sprays water over the plants. In my day as a student they were referred 
to as "fairy lavatories" because of the delicate fine spray they 
produced.

More realistically, why not use the time honoured method of allowing the 
 moisture tension in drying out soil (or compost) to cause water to be 
drawn up a substantial "wick" from a reservoir of water below the plant. 
This can be made quite nicely quantitative   (more or less) by having 
the reservoir calibrated and by recording the amount of water necessary 
to top up the reservoir. BUT you must have a good control set of 
unplanted soil to allow for the evaporation from the soil/compost 
surface.
Dr Peter Harris,
Department of Soil Science,(yes there is such a thing !!)
The University of Reading, 
Reading, U.K.

AKA P.J.Harris at reading.ac.uk

We also have some wicked computer simulations (home-grown) which model 
water loss from soils of various types under various climatic conditions 
with various types of plant.
Now then - cap that !