Nothing lasts forever, and fertilizer injectors are no exception. Part failures are often not discov- ered for days, even weeks. The best management practice is to test, maintain and calibrate often.
Fertilizer injectors are a mainstay of the greenhouse industry. They allow us to ap- ply large volumes of fertilizer while using relatively small stock tanks. They save labor, time and money, and for the most part, they work like a charm. We all have a tenden- cy to just assume all is well. Sadly, as my student and I found out recently, some malfunctions are not easily found until the crop decines. There are two types of mal- functions: absolute suction failure, and the much harder to discover injection degre- dation.
Here is a checklist to go through if you suspect your injector/proportioner is not doing the job correctly.
