Stomatal infiltration, the benefits it can provide, and the major factors influencing it are reviewed. Evidence of a role for spreading in the infiltration process is presented. The spreading and equilibrium surface tension of Silwet L-773 organosilicone surfactant (TSE8M; CAS Registry Number 27306-78-1) + cosurfactant blends have been measured and are compared with the levels of infiltration they achieve. It is shown that, in addition to requiring a low surface tension, stomatal infiltration requires a good spreading ability. Some other unknown factor(s) are also involved, and specific interactions with cosurfactants, and their ratios in blends, suggest those may be the nature of the surfactant aggregates in the solution. It is demonstrated that the infiltration of TSE8M can be extended by blending with select cosurfactants at an optimum ratio of 1 + 1, provided at least 0.2% TSE8M is used. By so doing, certain blends of 0.2% TSE8M + 0.2% cosurfactant are able to provide levels of infiltration comparable with those attained using 0.4% TSE8M.