R.W. Bosley
It has become increasingly obvious that if you are to compete in the field of container growing with the California nurserymen, then you must produce the plant in the shortest possible time. One of the requirements to achieve this is to try to maintain an optimum fertility level at all times. The level that you consider optimum well may change from week to week as the season develops, but the goal does not.

In searching for a means of doing this, we were very dependent upon Dr. Fred Peterson, of the Soil and Plant Laboratory, Inc., who with the assistance of Mr. Ed Kott, of the Milton Roy Company, developed the electrical component type proportioning system, previously utilized exclusively in industrial process control applications. I will try to illustrate and explain the operational characteristics of the system and show what advantages it has.

Bosley, R.W. (1969). A FERTILIZER INJECTION SYSTEM. Acta Hortic. 15, 37-39
DOI: 10.17660/ActaHortic.1969.15.8