I get DKNY, so what the heck is NPK?

Anyone who knows me will know I am not easily impressed by posh designer labels. Yeah I like quality products, but never get swayed into a purchase just because it’s a “label”. So, whilst I have heard of DKNY and even know that it stands for Donna Karan New York, when I kept seeing NPK mentioned in my gardening reads and had to chuckle. What is this…… a “Designer Manure”?

It seems that understanding a little basic chemistry can make one a better gardener. Knowing what different growing mediums are composed of, and what effect these ingredients have on the growth and development of a plant is useful.

I had grasped the fact that lots of nitrogen means lots of leaf, but I have lots more to learn.

So what is the NPK value I keep seeing?

N = Nitrogen; P = Phosphates; K = Potassium (Potash)

Okay, that I can grasp, so what do these nutrients do?


This is the nutrient plants need in the greatest quantity, it is absorbed to promote growth, leafy vegetables need a lot of it.

Phosphates (Phosphorus)

Phosphorous is needed by plants for cell division to occur, the result of this cell division is strong root and shoot development.


This is the nutrient that takes care of the metabolism of the plant. It allows steady growth, gives hardiness and disease resistance and is responsible for the colour and flavour of the fruit and vegetables.

Where can these nutrients be found?

I thought I’d try and find some compost ingredients that contained a balance of all three nutrients. From reading a few gardening books, I found the following ingredients that matched my brief:-

  • Worm worked compost (medium levels)
  • Seaweed Meal (medium levels)
  • Horse Manure (low levels)
  • Goat Manure (Medium levels)

To get a balance of high levels of nutrients it is clear that a little mixing is required.

For a high level of Nitrogen the following could be added to the compost:-

  • Urine
  • Dried blood
  • Bone Meal
  • Fresh Stinging Nettles
I know which one of these I’d prefer to use despite the risk of getting stung!

The next richest sources are:-

  • Poultry Manure
  • Strawy Stable Manure
  • Pea and Bean Vines

Then at the lower level there is:-

  • Grass Cuttings
  • Uncooked Kitchen waste
  • Annual Weeds
  • Fresh Seaweed
  • Animal Hair

Phosphorous is found in the following compost ingredients:-

The richest sources seem to be:-

  • Bone Meal
  • Fish Meal
  • Poultry Manure

At a lower level:-

  • Worm-worked Compost
  • Seaweed Meal
  • Goat Manure
  • Rabbit Droppings
  • Plant Ash

So now for the source of the flavour giver, the “Special K” Potassium (Potash)

There doesn’t seem to be very many rich sources, it seems these are the highest:-

  • Blood, Fish and Bone Meal
  • Chicken Manure
  • Wood Ash

Of course there is the option of purchasing a commercial compost, this will be balanced to suit, and it is having a little knowledge about NPK that can help when choosing the right one for the job.

One thing is for sure, there is so much more to learn and this, in my opinion, is the joy of gardening!

This entry was posted in Compost, Plant Nutrients and tagged , , , , , , , . Bookmark the permalink.

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