This blog accompanies my book “Out of the Scientist’s Garden”. The book is about how the world uses water in the business of feeding itself. It’s a serious book on a difficult topic, so I wrote in story form, through the lens of my fruit and vegetable garden. I kept the book free of tables and graphs because this type of information is for the specialist, and I was writing the book for everybody interested in water.
This blog will give a weekly update on growing sweet corn in my garden using waste water from the washing machine. I picked this subject because I am often asked about waste water and how to use it productively. More importantly, many irrigators around the world only have access to slightly salty water, and they use this to grow their crops. As we shall see, salt is a huge problem for irrigation.
Each week I will show a picture of the crop, report on how much water was used, and track the levels of nutrients and salt in the soil. This is also a pilot experiment to test some new scientific equipment we are developing. The equipment automatically measures how deep the washing machine water moves in the soil and the salt content of the water. The results are sent by mobile phone to the web. The weekly graphs will reveal what happens through the season.
The FullStop normally has a red or yellow float which pops up when water has been detected. In this case we have removed the float mechanism and installed an electrode. Electrodes were installed in wetting front detectors positioned at 200 and 400 mm depths. The electrodes will record when water passes these depths and record the salinity of the water. 
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