Recommend a Fertilizer Injector

[gentleben]

For the last couple years I have grown my tomatoes in fabric grow bags filled with Al's 5-1-1 mix. I have drip/sprayers set up for watering and been fertilizing by had with TTF.

This year I want to improve my yield by:

• adding a fertilizer injector
• pruning to two stems per plant
• growing two plants per large container
• fertilizing with Hydro-gardens 4-8-18 plus Ca(NO3)2 and MGSO4

I've searched here and other places and most recommend going with a dosatron unit, my main question is which one?

I will be growing about 18 tomatoes plus some herbs, lettuce and strawberries.

Any help on picking a unit would be appreciated. Do I need adjustable flow rate? What size of mixing container should I be planning for?

here's a pic from early in the growing season last year:


Thanks for any and all help, this is my first post, but I have been lurking for a while now and learned a lot.

[PureHarvest]

If you do the hydro-gardens ferts, you will need 3 injectors.
One for the tomato formula+mag sulfate, one for the calcium nitrate, and one for your pH adjuster.
The dosatron 14 gpm will run you $360-400 each depending on where you buy.
Then you will need pipe, fittings, a screen filter, and pressure regulator.
And then you will need a ph/TDS meter to check your work.
Then you need three 5 gallon buckets or rubbermaid trashcans for your 3 concentrates tanks.
You would make a concentrate of the 3 ingredients and each injector pulls from each tank to mix into your water line. Ideally you would have 1" pvc water line coming into the pressure regulator and filter side, the injectors would be plumbed in series next with threaded union fittings, then you would exit to a barbed fitting to your tubing. You could also exit to a plastic manifold that has irrigation solenoid valves to run to different zones. The valves would be wired to a cheap lawn irrigation control box to control when and how long each valves would open up. The rate of fertilizer is controlled by how you mix your concentrates, and how you have the injectors set.
So, you are approaching 2k for 18 plants.

The easier solution would be to get a big tank, tub, or IBC tote and make a master solution.
Basically, you fill your container with water, add each ingredient one at a time while stirring or agitating with a submersed pond pump.
You then have a large reservoir of already mixed diluted solution to send to your plants.
Hook your tube to the pond pump, and drop it into your tank and pump to your plants.

Lots of cheap ways to do this.

A five gallon bag with two plants will need roughly 2 gallons a day when mature.
So your set up will use 36 gallons a day.
You can get a 250 gallon IBC tote around here for around $100 or less.
Cut the top off it so you can access it easier for fillin/stirring/and cleaning.
Then you will only have to make fertilizer once a week.
Pond pump under $100
pH/TDS meter varies from $100-300
5 gallon buckets 3x$5=$15

So maybe $400 if you had to buy everything new.
Much less if you can find stuff on craigslist, or have stuff on hand.

You could plug your pump into a $10 digital timer to go on and off the same time everyday. You would manually run the system one time to see how long it takes to give the volume you need. You want 10% of the total volume to trickle out the bottom of each bag when you water. Once you know how long this takes, set your timer accordingly for each day.

[gentleben]

Pureharvest - first off, thanks!

I guess I was thinking of this all wrong. I thought I could mix up 50 gallons or so of diluted (plant usable) mixture of the 4-8-18, Ca(NO3)2, and MGSO4 which would be blended through the dosatron with the main irrigation water coming through the hose.

But that would leave me with very little nutrient at the plant. A 1200ppm mix added at a 1:100 ratio by the injector is only 12 ppm. doh!

Back to the drawing board. I don't think three injectors are in the cards due to cost and I don't have room for a 250gal tank in my yard.

edited to add that I just looked and I can get used 125, 150 or 250 IBC tanks locally here for $10, might have to see if I can find room....

[PureHarvest]

No problem!

FYI, a 250 gallon IBC tank only takes up a footprint of 40"x48" just in case you were thinking its huge. Stands about 4' tall.

[Cole_Robbie]

Injectors are based on flow rate. There are much cheaper siphon injectors, if your flow rate is high enough. My high tunnel drip tape used about 1.5 GPM. That was right on the verge of being enough flow rate to work, if I hung the bucket of fertilizer a few feet off the ground.

Hydroponics is cheaper than using an injector, at least on a small scale. There are many hydro methods that work. It is important to be able to keep the reservoir water cool. Someone posted on here a nice system made from 5" vinyl post covers. If you google "aeroflow" from General Hydroponics, the post cover setup mimics that machine.

[gentleben]

Thanks Cole_Robbie, I currently use a hozon running into a milk jug that I carry when I hand water now.

I tried hooking the hozon up to my drip/spray system, but the gpm was too low to get it to pull - I haven't tried elevating the fertilizer bucket but will try that once the snow melts and I get the system hooked up again.

I've looked into hydroponic systems, but right now that doesn't really interest me.

I'm also going to look into mixing and pumping from a larger (125+ gal) tank.

[Yak54]

Home Depot sells a 55 gal plastic drum for $79. You could plumb 2 together.

[gentleben]

Yak54 - good idea, a rain barrel (or two) might be a little more aesthetically pleasing to the neighbors and guests.

I'm also looking for a ph and ppm meter, can anyone recommend this bluelab one, or is there something else out there?

[Yak54]

I just bought the Bluelab truncheon meter. Don't have a ph meter yet, but soon. Probably I'll get the Bluelab PH pen.

[gentleben]

Rather than getting a large tank or using injectors I've decided to rework my irrigation system in an attempt to get high enough flows use the Hozon I already have to add TTT. I'll start with Urban Farms recommendations of 800 ppm for seedlings then 1100 ppm afterwards.

I'm switching over to pressure compensating netafim spray stakes for a couple reasons:
1. AKMark uses them
2. it makes it easy to calculate total gpm
3. I've had problems in the past with water running through my 5:1:1 mix and not wetting the media

The hozon is supposed to work with anything over 3 gpm. My calculated flow should be between 3.5 - 4 gpm, does anyone have any experience using a hozon on a drip system at that flow level?

Spring comes late around here, and this year is especially bad. I'm just starting to see some sprouts (I think I need a greenhouse):

[gentleben]

This year I'll be growing:
Bison
Sweet Scarlet Dwarf
Dwarf Crimson Sockeye
Merced OP
JD’s Special C-Tex
Roger's Best Black
Fred Limbaugh's Potato Top
Raspberry Mochi
Sudduth's Brandywine
True Black Brandywine
Lucid Gem
Pink Bumblebee
Mortgage Lifter
Brad's Atomic Grape
Black Krim

[Yak54]

You sure about GPM ? Maybe GPH.

[gentleben]

Pretty sure.

I plan to use:
- (16) 6.6gph spray stakes = 105.6 gph
- (12)10.6gph spray stakes = 127.2 gph

for a total of 232.8 gph which equals 3.88 gpm.

It'll be high flow, short duration watering.

[gentleben]

A quick update: I couldn't get the hozon to work.

After a bit of time on the mazzei injector selector site, I found one that would work with my flow and pressure, so I ordered it and it works! At a system flow of around 5gpm the mazzei is injecting at between 8-10gph.

[gentleben]