# Calcium Nitrate and Kelpak



## consettbay2003 (Mar 16, 2013)

How many ppm N does 1/2 tsp. of calcium nitrate per gallon of RO water provide?

For convenience sake it would be much easier if I could use Kelpak once a week when I fertilize. How much should I use per gallon? I realize every 2 weeks is the recommended time period between applications but my memory isn't what it used to be!


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## Ray (Mar 16, 2013)

You really need to know the mass of that teaspoon, as the bulk density will affect that, hence the final concentration.


Ray Barkalow
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## consettbay2003 (Mar 16, 2013)

1 tsp. = 6 grams


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## ALToronto (Mar 16, 2013)

6 grams would be the weight of water in 1 tsp. If your CaNO3 is as lightweight as mine, you would be lucky to have 3 g in a tsp. Pick up a small 'coke dealer' scale on Amazon; they cost around $10 and are surprisingly accurate. Volumetric measurements of powders are not reliable.


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## consettbay2003 (Mar 16, 2013)

1 tsp of my calcium nitrate weights 6 grams


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## goldenrose (Mar 16, 2013)

wouldn't using a TDS meter make this a lot easier? It's a relatively cheap investment.


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## Rick (Mar 16, 2013)

consettbay2003 said:


> 1 tsp. = 6 grams




Agricultural grade calcium nitrate (with 4 waters of hydration) is 11.9% N, and about 1% of that is from ammonia.

6 grams is 6000 mg, so 11.9% of that is 714 mg N. If you put that 6 grams into a gallon (3.785 L) then you get 188 mg/L N


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## gonewild (Mar 16, 2013)

1/2 tsp should be somewhere around 120ppm N


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## Rick (Mar 16, 2013)

gonewild said:


> 1/2 tsp should be somewhere around 120ppm N



For anhydrous?


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## gonewild (Mar 16, 2013)

Rick said:


> For anhydrous?



Based on the CaNO3 I used to use that is what it worked out. It is hard to weigh accurately because it absorbs humidity so fast the weight of a 1/2 tsp can be all over the place. I had it down to an approximate amount. But note I said somewhere around 120. If you come up with 94ppm using the math I wouldn't disagree.


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## TyroneGenade (Mar 16, 2013)

Teaspoons are very different to measuring spoons (as used in baking) as whether the spoon is level or heaped (or something in between) makes a huge difference in the mass of the solid being weighed. 

You can avoid the problem of spoons entirely by making a saturated solution of calcium nitrate. The solubility of the CaNO3 at 20 oC is 121 g/100 mL. If you need to add 10 g of CaNO3 to your fertilizing solution then you simply add 8.3 mL of the saturated solution to the fertilizing solution (you can use a syringe for this).


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## DavidCampen (Mar 16, 2013)

To be accurate you need to know if you have calcium nitrate tetrahydrate or calcium ammonium nitrate. Calcium ammonium nitrate is sometimes sold as "calcium nitrate 15.5-0-0". I would expect that the two might also have different solubilities in water. I prepare my calcium ammonium nitrate solutions at 400 grams per liter, I don't know if I have ever tried going more concentrated.


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## Stone (Mar 17, 2013)

If you want to be accurate you should also use an EC meter. 0.84gms/L will give you 100ppm N. If you read an EC of 0.84 dS/m you will have 100ppm N in 1 cup or 100 gallons. (with Calcium nitrate Ca(NO3)2 4H20)


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