If you have not booked your fertilizer needs, the University of Illinois suggests watching these Web sites for price trends: 1) The Fertilizer Institute price trends www.tfi.org/publications/pricespaper 2) The London fertilizer market www.fertilizerworks.com/ 3) Dept of Energy natural gas prices http://tonto.eia.doe.gov/oog/info/ngw/ngupdate.asp.