NPK kits are produced by a number of companies although you
may have to search around for them. They are similar to the
test kits used for aquariums. The problem I see is that
while these kits are expensive they contain quite low
amounts of chemicals. To reproduce such reliable titration
solutions you'll need to make up a comparably large volume
of stock solution. If done correctly, you'll end up with
more solution than you could imagine using. It will also
cost you far more than a quality kit, which will last you
ages anyway. There is no way you'll be able to economically
reproduce the solutions in these kits on the small scale. If
it was possible, there'd be DIY instructions on every
aquarium website.
Andrew

Andrew G wrote:

To be honest I have never seen a EASILY available NPK checking kit. I know
in Hydroponics there is a thing called a truncheon(sp??) meter which will
simply check the nutrient level. It gives a readout of a number, that's all.
Different veges require a different level of nutrient to grow in.
I have no idea what chemicals are used in soil NPK tests. But, did you know
different pH unlocks/allows different nutrients in the soil? So if your soil
reads 7.5, it will have different nutrients available then the same soil at
6.5, and so on.
So getting pH test kit that gives you a number figure, rather than just
telling you if it's acid or akaline, then getting hold of a chart telling
you what nutrients are available at what levels of pH would be the easiest
and cheapest. IIRC even the yates garden guide book had such a chart.
Yup, I know this is useless if the soil is lacking a nutrient. This only
tells you if a nutrient would be available, but the nutrient has to be there
in the first place. But can be corrected with good use of fertiliser and
organic matter.

As I said Ive never seen such a easily available kit, but of course they
would exist.
Failing that, I'd be finding another NG, something dealing with chemistry or
biology perhaps.

"Monte" wrote in message
...
I know you can buy the things, but I'm stubborn and curious.(and still
alive to tell about it) heh

What I am looking for is what reagents etc are used for the standard tests
for NPK? hey, even I can use litmus so the Ph thing is whipped.

any help appreciated, seems all the 'experts' want to sell you their
personal kit or service.

Monte