The necessary software for browsing the web and sending e-mail is included with your subscription to a provider. Microsoft Windows operating systems allow the most options for network usage. Most software today is configured for Windows 95. You can buy other software packages to enhance your web browsing capabilities, but the free stuff is more than adequate in my opinion. In addition, there are several web sites which let you download free software.
PET stands for potential evapotranspiration and is becoming widely available in Texas.
Computers and weather stations now make it easy for us to use PET for daily decisions on irrigation. Agricultural scientists have devised a reference ET rate based on a reference crop from which we can determine the actual water requirements of all other crops. The water requirements of individual crops are determined from the PET through crop coefficients for a particular crop. These crop coefficients vary depending on the stage of growth of the crop because of the different amounts of water used by the crop in different growth stages. In addition to daily PET, the Texas PET Web Site contains a wealth of information on how to use PET for irrigation scheduling.