If npk are just ratios can't someone explain why nutrients would be labeled 10-10-10 when they could just be 1-1-1 and get the same point across?
When raw materials are formulated into "Nutrients with Guaranteed Analysis" atomic weights are used for the formulation of nutrients (powdered or liquid/ organic or inorganic same thing) These numbers are confusing but are the best indication short of bringing a chemist with you the next time you need some new nutrients from the store....10-10-10 or 1-1-1 will have varying amounts of filler, such as; water ( in liquid nutrients) , clays (in powdered time release nutrients) are two examples. The actual inerts are not usually revealed. The 1-1-1 may in fact contain more nutrients than the 10-10-10. comparing apples to oranges quality to crap.
As Allienwidow said, "Well that's why you use liquid nutes with guaranteed values." That's why I do to. Good food all the way to crappy food - use the same method to give you the nutrient analysis. Stick with a good source that you trust. Use the directions as your guide to mixing and feeding.
I ve tried to keep this simple as not to require a degree to figure out what im saying
When I started using hydroponics we couldn't buy nutrients premade. We had to make our own.
Start with potassium nitrate , calcium nitrate, magnesium sulfate, ammonia nitrate, chelating agent, trace elements ect,ect ,ect. I couldn't call up company X and get instructions, as like computers, they just didn't exist for some underground grower. I had to use atomic weights to figure this out and/ or risk killing my crop. Now a days we just go down and buy some jugs of "nuts with guaranteed analysis" follow the directions and we are growers. This is so much easier and the N-P-K numbers are an indication of the relationship between these various compounds to make things easier for the consumer.
"i need a food with high nitrogen" - well get the 51-0-0 as an example ( full of nitrogen, no phosphorus or potassium - and lots of inert fillers too.)
In furtherance to the above example it doesn't tell you the source of nitrogen which may be a factor of importance. Nitrate nitrogen is quit different than ammonia nitrate- but both make up the number for "N'. Both are important forms of nitrogen - but used for different purposes within the plants system.
Hope this helps - don't read too much into it - go grow some herbs and have fun
Peace and Pot