Dosing Nitrogen > what counts, elementary or molecular

[Kosmo83]

Hi,

i have now a maybe small problem in interpretating scientific papers and the advises for dosing fertilizers.

There are numbers like "25ppm of nitrogen for every watering"
What kind of nitrogen ? The elementary or the molecular ?

And there are now the next issue, the type of "nitrogen"

1g of nitrate has only 0,226g of nitrogen
1g of ammonium = 0,777g nitrogen
1g urea = 0,467g of nitrogen

K-lite (normal variant) has 12,3% nitrate and 0,6% of ammonium
So 2,78% of nitrogen from nitrate and 0,47% from ammonium.

So only 3,25% N in total (a quater of the declared nitrogen)

So... if you give 25ppm calculated with the written nitrogen, than you give only arround 6,5 ppm elementary nitrogen!

All scientific papers and article say, the most important part of a fertilzer for growing orchids is nitrogen!

So, it can't be unimportant which type is important.

For me, it has to be the pure N, because that's what the plants use, the form is only like a chelat (EDTA etc.) and is just a source for nitrogen

@Ray what do you think ?

---------- Post added at 11:39 AM ---------- Previous post was at 10:17 AM ----------

My observation : I mix a fertilizer for my cattleyas myself, the idea of k-lite as baseline.
But between early dec and early january, I waited for some ingriedients so I used normal Peters Grow-Mix and Hakaphos Azerka (20-7-10+3MgO).
​Under my 280 watt HCI-Lights, my BLC. King of Taiwan becomes a bit purple, so I can see how fast she grows by green stripes of new leaf-tissue that wasn't exposed to light.

This green stripes became a lot smaller since I my fertilizer with 10-3-4,5-(+7,3 MgO), dosed to 50PPM Nitrogen, these stripes became a lot smaller, but the root-grow was more.