I installed a Dosatron Fertilizer Injector http://www.dosatronusa.com/markets-served/horticulture.aspx in my greenhouse. It has a range of 1:50 all the way up to 1:500. It will surely make it a lot easier to fertilize all of my trees, and misc. plants. I have it set on 1:50, meaning every time 50 gallons of water goes through the hose the Dosatron will automatically inject 1 gallon of fertilizer directly into the hose water. By adjusting the concentration of the fertilizer solution, one can inject just about any ppm desired. Also by attaching a spray nozzle on the end of the hose it will be easy to apply a foliar spay, insecticide spray, or fungicides in a snap. - Millet (536-)

Millet, how large is your greenhouse?

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Tri, the greenhouse is 32'W X 72'L X 11'H

Millet (535-)

Now that a Dosatron fertilizer injector has been installed in the greenhouse, which injects fertilizer directly into the water line, the fertilizer schedule is going to be changed. Fertilizer now will be applied at a lower rate, but more frequently with every watering. The constant fertilizer program will apply 200 ppm N with each watering. I wasn't sure whether to apply 150 ppm N, or 200 ppm N, so I just arbitrarily chose 200 ppm. We will see how it does. - Millet (526-)

I believe that water with additives should be the best way to water in my sandy soil. Lately we have been getting hard rain every day. It is highly likely the granular fertilizer I applied a week or so ago is history now.