Citrus Growers Forum

Sylvain · Posted: Mon 05 Jul, 2010 6:41 am

Danero, I edited my previous post.

danero2004 · Posted: Mon 05 Jul, 2010 3:29 pm

"could be too low" as a bad ratio for a daily watering or low as in total amount per month ?
Should I increase to 3 grams / 3 l water , or leave it just like it is now

thanks

danero2004 · Posted: Sun 04 Sep, 2011 7:53 pm

jrb wrote:

Calculating ppm is a mass calculation, not a volume calculation so you have to convert your volume units to mass. 1L of water = 1000g.

For example, if you want 1000g of solution and you want to fertilize at 250ppm Nitrogen you would multiply the total mass of the solution (1000g) by the desired concentration (250ppm or 250/1000000) and divide by the concentration of nitrogen in the fertilizer (6% or .06).

The mass of your fertilizer for 1000g of 250ppm Nitrogen solution is

(1000g)*(250/1000000)/(.06) = 4.17g

For the total solution

4.17g fertilizer + 995.83g water = 1000g of 250ppm nitrogen solution

Adding 4g of fertilizer to 1L of water is close enough.

If you do not have a gram scale then volume measurements are more convenient. To convert 4g to a volume measurement you need to know the density of the fertilizer.
I just measured the density of the fertilizer I use and it is 0.845g/mL. Your fertilizer may be different.

To convert 4.17g to mL:
(4.17g fertilizer)/(0.845g/mL)= 4.93mL fertilizer

5mL fertilizer mixed with 1L water is close enough.

I've used this formula and it worked great so far but just a simple question :
Based on this "How many milliliters in 1 grams? The answer is 1.We assume you are converting between milliliter and gram [water]" it seems that in water (which is close to soluble fert,) is the same ratio , so should I use (1000g)=(1000ml) ? when I want to calculate the correct ratio of a soluble fertiliser or should I use another type of conversion ?

Stoddo2k11 · Posted: Mon 05 Sep, 2011 12:49 am

danero2004 wrote:

I've used this formula and it worked great so far but just a simple question :
Based on this "How many milliliters in 1 grams? The answer is 1.We assume you are converting between milliliter and gram [water]" it seems that in water (which is close to soluble fert,) is the same ratio , so should I use (1000g)=(1000ml) ? when I want to calculate the correct ratio of a soluble fertiliser or should I use another type of conversion ?

The calculation is based on the density of water which is 1g/ml (or 1g/cm3 or 1kg/L, etc.). Since water is the solvent then 1g/ml is a close approximation. If the fertilizer (or other solids) was dissolved in ethyl alcohol then you would look up the density of ethyl alcohol for the calculation. Obviously most everything we deal with has water as the solvent.

But, keep in mind why the 1g/ml is such a close approximation - in 1 gal of water I only put 1-2 tsp of liquid fertilizer in (for a hydroponic system), plus the liquid fertilizer has water in it too. In other words its 95%-99% water anyway.

danero2004 · Posted: Mon 05 Sep, 2011 2:44 am

So you say I should replace with the ratio 1000ml ? being almost the same.

Millet · Posted: Mon 05 Sep, 2011 4:16 pm

1 ml = 1g is ONLY true for pure water at a specific temperature.

Following is the definition of PPM: 1 mg of something in a liter of water is 1 PPM.

danero, if you have a FAX number I will sent you the calculations to on how to determine the ppm of any fertilizer solution you desire to make. - Millet(498-)

danero2004 · Posted: Fri 16 Sep, 2011 5:50 pm

...me again... Very Happy

we all have been calculating the ppm ratio of N but when we are using different products , even from same company...like Peters profesional(scotts) who makes 2 types 23-6-10 close to 5-1-3 (allthough I'm not sure if this is also good for growing trees in pots) and also some Substral 6-3-6 ratio with good Iron and Mg ratio

But if you see there , we have x-x-10 x-x-6 so what about the other numbers , don't we deal with some high level of the last two when calculating only N , and not the K or even P which can lead to root poisoning.

Is it safe ?....Many producers have different NPK ratio , I also read on one bottle a citrus fertliser with some crazy numbers 6,3-6,4-10,9 Shocked

thanks