While not the highest lab quality you can certainly interface pH probes even the IFET types. There are many examples on the net and having reverse engineered several commercial meters I can assure you some of the designs are are quite good actually, although more geared for our(OSHW or educational) usages then mass production. You can find out how to build a basic one http://www.sparkyswidgets.com/Projects/pHInterface.aspx and there are links to some other designs and app notes as well. With a little bit of patients and some guidance you should be able to have something reading this quite quickly, let us know how it goes.
Also yes Docedison even spinach, cabbage, tomatoes and strawberries(or whatever) need properly pH'd water with the right amount of fresh nutrients. Right now I have 2 spinach plants, 2 cabbage, a strawberry and a tomato, all in an high pressure aero "table" running off a 12v battery, an inverter and an arduino style controller board. So far so good on this experiment 