In the course of final research for the SARE Grant Project as of the Spring of 2013, we found one vendor at this point, Monnit, that's most affordable, easy to use and that has the best support mainly for temperature and humidity monitoring. Another vendor, Mojyle, combines Monnit sensors with other types of sensors including soil moisture and leaf wetness but it is a very small company with less of an ability to provide technical support. Another company, NHR, in Taiwan has good, affordable sensors but is in Taiwan, with no U.S. presence at this time.
The AvidWireless solution looks very interesting especially for GPS tracking is important. We have not been able to test this companies equipment.
n a different category are weather stations which don't operate in combination with other sensors but provide basic readings in one package for rainfall, wind direction and speed, temperature and pressure. We have had great success with a couple of more affordable weather stations . See our Weather Stations section for a summary. However, if you are primarily interested in higher end weather station type sensors then the Onset Computer Corporation or Rainwise Inc solutions may be the best but more expensive.
See the links under Vendors/Consultants for detailed descriptions of these vendors.
If you search the web for wireless sensors you see dozens if not hundreds of companies are providing sensor solutions for many different industries. As of the spring of 2016 the vendors we list appear to be best for New England farmers but that could change at any time. Please let us know if you locate vendors or solutions we should consider and include on this site. As you know technology changes very fast these days and it changes especially fast in this field so you will need to contact the vendor you plan to work with for current information.