Garden Irrigation – Newtry Fertilizer Injector

For most of my drip irrigation setups, I use the Dig 1 Pint Proportional Fertilizer Injector I get from Drip Depot.

House Front Drip Setup

They work well, but do not hold a lot of fertilizer, and I have to refill them for each zone after fertilizing one.  With 16 zones and counting, I spend a lot of time just refilling the injectors on the weekends I’m fertilizing, which lately has been almost every weekend.

I have researched many of the various fertilizer injector options available.  I have tried some of the venturi-type injectors, with no success.  The issue I have with these is that my zones are not that big, and thus do not generate that great of a flow rate.  With the measured flow rates on some of them only putting out 1 to 2 gallons per minute, this low flow rate is not enough to generate enough vacuum across the venturi to draw the fertilizer up.

The hydraulically powered proportioning injectors have really intrigued me, but the price of most of them was way more than I was willing to spend.  Enter the Newtry Fertilizer Injector for Drip Irrigation.  They have several models, with proportioning percentages in ranges from 0.2 – 2%, 0.4 – 4%, and 1 – 10%.  I chose the 0.4 – 4% model.

Portable Injector System

I attached a check valve, filter, short hose, and male hose quick-connect adapter to the inlet side, and a flow meter, shutoff valve, and female quick connect adapter to the outlet side.  I mounted the complete assembly to a hand dolly, so I can move it to the 5 timer stations around my garden.  Adding quick-connect adapters to the hoses on the timer assemblies allows me to easily connect this injector to the timer stations, and fertilize the attached zones.

I use the 2 1/2 gallon jugs that kitty litter comes in to mix and dispense my water soluble fertilizers into the system.

I also connect a regular hose to the outlet so I can fertilize plants manually with a hose.  I would normally use a hose-end fertilizer to do this, but this makes that process easier.  I only have to mix fertilizer in the jugs I use.

Another benefit is I can use different types of fertilizers, and just have to move the suction hose into the fertilizer I want for that zone.

So far, this injector works very well.  The zone that our corn and sweet potatoes is on does not have very many emitters, and therefore a low flow rate of 1/2 gallon per minute.  This injector handled it just fine, continuing to inject the fertilizer at the set dosage.