Rather than basing a herbicide program for all fields on the weed spectrum in one primary field, weed control would be more successful if what's in each field is considered even if that means changing the tank mixture from field to field. For example, if hairy nightshade and redroot pigweed are the dominant weeds in a field, then there are relatively many two-way herbicide combinations that could provide season-long control control of both weeds e.g. Matrix + Eptam, Chateau + Sonalan, or Outlook + Prowl H2O. However, the mixture including Prowl H2O would be more effective on a nightshade - lambsquarters combination than would the other tank mixtures. Therefore, tank-mix partners may need to change multiple times even if some are more expensive than others. In fact, depending upon factors such as weed density and species number, three-way tank mixtures might be necessary in some fields, but not others. A Tank Mix Partner Choice Chart has been developed to help determine the best herbicide combinations for multiple weed spectrum scenarios.