Adding NPK Ratio's

[Toleman]

Not sure this is the correct section but you lot appear to have the biggest mathematical brains. That's a compliment BTW :)

How do you work out the new npk value of an equal mix of fertilisers?

Grow nutrient is: 2-1-6
Bloom nutrient is: 0-5-4
Micro is: 5-0-1

This is mixed using 1ml of each per litre of water (I know this doesn't affect NPK) assuming I am using pure water with no water board added minerals.

Chris

[factor-fiction]

I've never used npk but a quick google search shows me that 2-1-6 for example means 2% Nitrogen (N),1% Phosphoros (P) and 6% Potassium (K), so presumably the content of the other 91% is not relevant here.
Another site says though that when you mix fertilisers you have to go by teh relative weights not the relative volumes. If you were adding equal weights you could simply add the figures for each element and divide by 3.
So in your case if you were to add equal weights:
N would be (2+0+5)/3= 2.3
P would be (1+5+0)/3=2
K would be (6+4+1)/3 =3.7

But you are advised to look on some relevant sites such as maybe this:
http://www.gardenscur...-i-calculate-npk.html

[Toleman]

Thanks for taking the time to reply.

Chris