Fertilizer injector concentrations

[Darold Petty]

I have a small Dosatron fertilizer injector to provide a large quantity of fertilizer solution. My injector is set to a dilution rate of 1:100 and the concentrate tank is 10 gallons capacity.  This will produce 1000 gallons of solution.  In the past I attempted to scale up fertilizer based on one tablespoon per gallon of water so I would add 1000 tablespoons of fertilizer to the tank.  I am trying to be more accurate about the actual concentrations.  The most recent soluble fertilizer I purchased addresses this question in Parts Per Million based on the Weight of the fertilizer.

  What is the correct PPM level for seedling and small, potted palms ?  Furthermore I don't understand the table on the back of the fertilizer package.  

  The instructions say to "multiply the 100 PPM figure by 1.50 to obtain 150 PPM.  This is simple, but I don't know how to incorporate this with the percentage of NPK shown on the left hand column.  The left hand column says for 5% NPK use 27 ounces at the 1:100 injector ratio, but for 10% NPK use 13.5 ounces.  This seems backwards, wouldn't one use more fertilizer for a higher percentage of NPK?   The older I get, the more stupid I feel !  

What amount of fertilizer by weight should I use in my 10 gallon concentrate tank with the injector rate of 1:100  ??  Thanks very much ! 

[Yort]

Just measure electronic conductivity of your solution, should be around 2 mS/cm3 depending on the species maybe a bit less. Becouse you also need to know whats already in your water. There are lots of cheap EC meters available that work well enough for home use.

[Nakheel1412]

Hi @Darold Petty !

The whole table gives the appropriate values for 100PPM (it's written in bold right below "For example ...") ;
Since you need a 100PPM concentration, and your injector's dilution rate is 1/100 , you can directly read the appropriate values in the 1:100 column ;

Now that you now what column you should refer to, you need to know how concentrated your concentrate originally is ;
If your concentrate is a 5% concentrate, you need to place 27 onces of concentrate per gallon in your injector's concentrate tank to get 100PPM ;
If your concentrate is more concentrated, like 9%, you need a lower volume of concentrate in order to get a solution with the same concentration, i.e. 100PPM (here, for 9%, 15 onces)

You do not already have a concentrate, therefore you need to prepare it ;
Let's say you want a 5% concentrate ;
-> To fill your injector's tank, you need 10 times 27 ounces of a 5% concentrate (10 times because 27 oz id for 1 gallon, and your tank is 10 gallon);
To get a 5% concentrate, you need to add 5 parts of powder to 95 parts of water ;
Since you need 27 ounces of concentrate per gallon, you prepare a concentrate with 25,65 oz of water + 1.35 oz of powder for a 1 gallon tank;

EDIT : Red = what I forgot
Because your injector's concentrate tank is a 10 gallon, you need to make 10 times 27 ounces = 270 ounces of concentrate, since 27 ounces is for 1 gallon ;

Now that you have your concentrate, you place it in your injector's concentrate tank, and you're good to go !
(you're good to go after filling the concentrate tank with water, i.e. adding to the 270 ounces of concentrate enough water to get 10 gallons)

(Sorry if I made linguistic mistakes, English isn't my native language, I hope my explanation is clear enough)

Edited May 4, 2018 by Nakheel1412

[Nakheel1412]

Sorry @Darold Petty, my explanation was incomplete, if you already read it come back, I fixed it !

[Nakheel1412]

My bad, I misread your post, I thought you wanted to know how to get a 100PPM concentration ;
I have no idea how much fertilizer palms need in terms of PPM, you probably need to ask large nurseries that use such systems to feed their palms ;

[Keith N Tampa (ex SoJax)]

A common concentration range is 100-200 ppm Nitrogen applied as a constant liquid feed (CLF).  This would be fairly common for well watered, fast growing greenhouse crops like poinsettias, mums, hanging baskets, etc.  Bedding plants can be grown with 50-100 ppm N and this lower concentration would probably work for slow growing palms in a cool climate.  If a plant is growing vigorously it will need more fertilizer than if its not so don't apply much fertilizer if the plant is quiescent (or dormant) regardless of the cause (temperature, drought, low light, root bound, etc).   And some plants just grow rapidly so they will be heavier feeders...think Washingtonia robusta vs Ceroxylon, for example.  The Washie would need more nutrients.  I would not go above 400 ppm N except in very specific circumstances and never on a constant liquid feed basis.  This is a generalization, of course, but at least its a place to start.

There are many factors that go into selecting the right fertilizer, not just the right concentration; the major ones being water quality, soil properties and plant/crop requirement (Celery is going to need much more nitrogen than a palm, for example).  

Also, if one is using a controlled release fertilizer, the amount of soluble fertilizer should be reduced.  Most commercial nurseries use controlled release fertilizer as the primary source of plant nutrients, not soluble.  However, there are exceptions, and soluble fertilizers are good plant toners for commercial nurseries that know how to use them.  Due to the complexity and resultant verbosity, this forum is probably not the right place for such as conversation.  

Being in the fertilizer business for over 20 years, I use both controlled release and water soluble, but the vast majority of the nutrients come from the controlled release fertilizer source.  I just don't want to mess with liquid applied fertilizers all the time.  Also, one good rainfall and the soluble fertilizer is lost.  Thats not as big an issue in CA as it is here in FL, but its still something to consider.  

[TexasColdHardyPalms]

@Darold Petty Will you confirm that your are using this in a drip and not through a sprinkler that will hit the foliage? That makes a big difference as well. 

[Darold Petty]

I only use it for hand watering in my greenhouse, and only about every third irrigation. Thanks to all for the great information !

[Tyrone]

Darold, I've never used fertigation so take my comments with a pinch of salt, but without knowing what your palms really need I would start with the lowest dosage and slowly and carefully over time up the dosage and see what happens. Look for brown tipping of leaves etc to tell you if you've gone too far. My thoughts are that a consistent but lower dosage would work way better than a higher dosage every now and again. Take accurate records etc so you can compare at a later date. I'm interested in your setup as I'm planning to install a 23000L tank with possible fertigation setup but mainly for fish and seaweed emulsion injection over the landscape.

[Keith N Tampa (ex SoJax)]

  On 5/5/2018 at 12:33 PM, Tyrone said:

Darold, I've never used fertigation so take my comments with a pinch of salt, but without knowing what your palms really need I would start with the lowest dosage and slowly and carefully over time up the dosage and see what happens. Look for brown tipping of leaves etc to tell you if you've gone too far. My thoughts are that a consistent but lower dosage would work way better than a higher dosage every now and again. Take accurate records etc so you can compare at a later date. I'm interested in your setup as I'm planning to install a 23000L tank with possible fertigation setup but mainly for fish and seaweed emulsion injection over the landscape.

Expand  

That’s good advice Tyrone.  Seaweed brings all kinds of good things like amino acids, fulvic acid, etc.  fish emulsion, otoh, concerns me as we are depleting fish stocks at a precipitous pace and catching them for use as fertilizer for terrestrial plants seems like a bad idea.  Concentrated Fertilizers mined from Earth are not inexhaustible either, but they aren’t really part of the ecosystem the way living things are.  The sea is under tremendous pressure due to over fishing and pollution.  

 

 

[Pip]

  On 5/5/2018 at 1:31 PM, Keith in SoJax said:

That’s good advice Tyrone.  Seaweed brings all kinds of good things like amino acids, fulvic acid, etc.  fish emulsion, otoh, concerns me as we are depleting fish stocks at a precipitous pace and catching them for use as fertilizer for terrestrial plants seems like a bad idea.  Concentrated Fertilizers mined from Earth are not inexhaustible either, but they aren’t really part of the ecosystem the way living things are.  The sea is under tremendous pressure due to over fishing and pollution.  

 

 

Expand  

In Australia  many of the rivers are over  run by invasive introduced species  fish, mostly  carp. Carp are not considered  good eating  and environmentally distructive, so making fertilizer  with them is seen as benificial.

[Palmsbro]

  On 5/5/2018 at 1:50 PM, Pip said:

In Australia  many of the rivers are over  run by invasive introduced species  fish, mostly  carp. Carp are not considered  good eating  and environmentally distructive, so making fertilizer  with them is seen as benificial.

Expand  

Cane toads, which are extremely invasive in the northern half of Australia, are also sometimes used to make fertilizer.

Some US states also have heavy Asian Carp (same kind that is invasive in Australia) infestations.

This means for a lot of future fertilizer for our palms. 

[Keith N Tampa (ex SoJax)]

  On 5/5/2018 at 1:50 PM, Pip said:

In Australia  many of the rivers are over  run by invasive introduced species  fish, mostly  carp. Carp are not considered  good eating  and environmentally distructive, so making fertilizer  with them is seen as benificial.

Expand  

That IS a great use for invasive Fish!  

[Keith N Tampa (ex SoJax)]

  On 5/5/2018 at 2:28 PM, Palmsbro said:

Cane toads, which are extremely invasive in the northern half of Australia, are also sometimes used to make fertilizer.

Some US states also have heavy Asian Carp (same kind that is invasive in Australia) infestations.

This means for a lot of future fertilizer for our palms. 

Expand  

To quote the Beatles, “Let it be”.  

[Darold Petty]

Ok, Now I have the answer to my original question !  .

  To calculate the Parts per Million level (PPM) of nitrogen (N), do the math as follows...

Start with the N value listed on the soluble fertilizer packaging.  Mine is  Romeo 15-5-15.  Use the N value of "15".

Find 15% on the left hand column of the table, then scroll to the right until you reach the column for your injector ratio (mine is 100:1)

This quantity is 9 ounces (9 oz) for 100 PPM.  I want 300 PPM for once-per-month fertilization, so multiply 9 oz times 3 equals 27 oz. 

My concentrate tank holds 10 gallons, so 27 oz times 10 equals 270 ounces of fertilizer to make up a full tank of concentrate.  

270 ounces equals 16.88 pounds of fertilizer.  I use a baby scale to achieve an accurate weight of fertilizer.