using a fertilizer injector system for fertilizing plants

[flplantguy]

Does anyone here use an injector for liquid fertilizer on your plants, and if so what do you think about it? I'm considering doing this for my plants, since I used one for my orchids before (and will again) since it works so well for them. I had a minidos that was great.  What are the pros and cons to it?  I could do direct with every watering or on an as needed basis too.  They are generally for larger grower operations but the minidos is just small enough to be used in a home setting. Otherwise it's a Venturi style that's hit or miss for dosage so I want to avoid that.  Granular fertilizer on some tropicals can be hit or miss (no soil to hold them on vandas) so I'm looking at the best way to accomplish it for everything all at once if I can.

[Darold Petty]

I have a low volume Dosatron, running at 300 ppm, and I love it !  Further details later,  

[Darold Petty]

I purchased this Dosatron unit several years ago.  I have two water lines from the house to my greenhouse, clear, potable water, and pre-mixed fertilizer water, running at 300 ppm (parts per million) with a soluble fertilizer, 15-5-15 NPK and all micronutrients.  My irrigation manifold has numerous  ball valves, allowing me to direct the fertilizer water to the greenhouse and/or any of the landscape irrigation circuits.  The concentrate tank is 15 gallons, and it is a food grade type of plastic that is completely inert and non-reactive.  I use a magnetic drive water pump to develop a strong mixing current in the concentrate tank.  ( this pump was left over from my salt water aquarium. )  The Dosatron product info suggests that the unit should be disassembled and cleaned after every use.  I have never done this, and the unit has performed flawlessly for years.  I love having an unlimited supply of fertilized water, running at 60 psi.  I usually irrigate with clear water two or three times, then switch to fertilizer water about once per month.  I direct the fertilizer water through the landscape circuits two or three times per year.  The irrigation timeclock is an Irritrol MC-8, purchased and running since 1983.  It is as dependable and steady as gravity.  I use ball valves in the greenhouse for the two water sources, with quick connector fittings, it takes just seconds to switch the hose between the two water sources.

I have included my hand written instructions about the calculation needed to produce a fertilizer solution for any given level of ppm.  Using these calculations I add 100 times the amount of soluble fertilizer to the concentrate tank, while the Dosatron is set for a 100-1 mixing ratio of clear water to the concentrate.  The concentrate will develop a scummy layer on top of the liquid after several months, but this is benign and is easily skimmed off.   This is a fantastic system, and I am fortunate to be handy with plumbing !

( I am a retired home improvement contractor )  

[flplantguy]

Wow that is impressive! Is that to supplement slow release fertilizers or just alone?  I like the idea of a strong organic soil that needs little fertilizer, except a very weak solution every once in a while that the orchids get too.  I think thats either a pipe dream or a long way off and a ton of work.  I worry about the sand leaching also so thats something i need to learn more about.

[Billeb]

47 minutes ago, flplantguy said:

Wow that is impressive! Is that to supplement slow release fertilizers or just alone?  I like the idea of a strong organic soil that needs little fertilizer, except a very weak solution every once in a while that the orchids get too.  I think thats either a pipe dream or a long way off and a ton of work.  I worry about the sand leaching also so thats something i need to learn more about.

I too use a Dosatron unit like @Darold Petty for my fertilizing. I had to buy 2 units though, one for the front yard and one for the backyard so it wasn’t a cheap endeavor. 
 

My units are set to 120:1 and my solution is about 200ppm. I’m also using a water soluble fertilizer 18-6-18 so it’s a similar ratio to Darold but slightly increased NPK. 
 

When I first hooked it up, I had it on a constant feed schedule but after about a month, I noticed a few plants had what looked like leaf burn / discoloring. It scared me and I figured I was over fertilizing. What I do now is simply  turn on the Dosatron every month or so (when I remember). I built a Maint loop for each Dosatron in the plumbing so it allows turning the Dosatron on and off manually via ball valves. I haven’t had any issues with leaf burn since quitting the constant feed but have had great results. I’m on Drip irrigation obviously and I topcoat my planters with a few inches of organic material annually so it was always a real pain digging down to the emitter and throwing a pile of PalmGain below. The Dosatron is 1000X easier. 
 

One thing that was told to me regarding constant feed vs sporadic feeding is constant feeding is typically utilized on potted plants (in a Nursery) instead of garden plantings. With potted plants, the solution can run thru the pot and out the bottom. Basically just temporarily coating the roots. With garden planting, the fertilizer solution has the ability to pool and saturate the roots so they are essentially sitting in fertilizer depending on soil medium. I think that’s what happened to me. Maybe not, but it makes sense. 
 

I always heard liquid fertilizing was the way to go. I’m a big proponent if you can do it. Good luck!!

-dale 

 

Here’s my front yard unit when I used a 5G bucket for the solution which has since changed. I also put a hose Bibb after the Dosatron in case I want to fill up a watering can with diluted fertilizer. 🤙

[flplantguy]

Buffering a high pH isn't too hard but what about rainwater matching? I want to take my high pH water (about 8.5 to 9 with low TDS) and get it closer to rainwater, but im not sure how to get the other chemistry into it, or if it matters. Rain has dissolved elements in it that seem to get a response from plants, but can it be created?  Since the raint season here is so sporadic and short i want to keep them growing that same way as they do during good rain events. Try to mimic Hawaii or native ranges as much as possible for that ideal growth rate. I see a difference in water vs rain on mine and after a rain, just like orchids, they respond faster.