N-P-K

[gunrunner]

Just wondering if anyone has ever determined the n-p-k for compost?


Mike

[Worth1]

It can't be done there are too many variables making it.
Worth

[carolyn137]

Originally Posted by gunrunner

Just wondering if anyone has ever determined the n-p-k for compost?


Mike

Mike, wouldn't it depend on whether someone was making their own compost piles, as many do, where no two would be the same b'c of different stuff put in the compost piles? I think that's true and thus no way to determine NPK.

I have no experience with bagged purchased compost, if even that exists, but if it does exist perhaps the NPK would be noted on the bag.

So I'll let others comment about purchased compost.

Carolyn

[RayR]

Carolyn, I've not seen NPK claims listed on bagged compost for good reason, since no compost is exactly alike, the NPK is variable. I don't even see why NPK is important since it is a biological product in a constant state of change.

[AlittleSalt]

Everyone posting above is correct. Even if you used the same amounts of the exact same ingredients every time you make compost - the NPK and other various change due what time of year they are selected and at what growth stages, growth conditions, etc.

[Worth1]

Originally Posted by RayR

Carolyn, I've not seen NPK claims listed on bagged compost for good reason, since no compost is exactly alike, the NPK is variable. I don't even see why NPK is important since it is a biological product in a constant state of change.

I agree, NPK is a byproduct and is not the intended use for compost.
Compost is a soil builder.
Worth

[amideutch]

This year I saw bagged compost for the first time and bought a 40 liter bag for my tomato plant out in the next door neighbors garden.

The name on the bag was Garten Kompost (Bio Active) and was in a 40 liter Bag.

Here are the contents in NPK listed for the whole Bag.

N 0.70%
P 0.30%
K 0.50%
Magnesium 0.50%
Cadmium 0.25%

As said above every compost source will be different.

Ami

[RayR]

Ami, I know nutrient analysis works a bit different in Europe but I didn't know Cadmium was now on the list of essential and beneficial minerals.

I know you meant Calcium. At least I hope so.

[carolyn137]

Originally Posted by RayR

Carolyn, I've not seen NPK claims listed on bagged compost for good reason, since no compost is exactly alike, the NPK is variable. I don't even see why NPK is important since it is a biological product in a constant state of change.

As I said above, I didn't even know if there is bagged compost for sale and that's why I asked others to answer.

Around here in some places when the leaves are picked up in Fall, they do that in the village near me, but I don't live in the village, and they also will pick up bundles of small twigs, they take it back to the garages/landfill area and chop up everything and then you take your own bags to fill and take home.

Carolyn, who notes that on her lawns the leaves are left to rot b'c everything here has a rock base and in a few hundreds of years those rotted leaves should help create some decent soil.

[Elagrow]

You can get a NPK tester for soil, it should get you a fair reading, but it wont be exact.

[Gardeneer]

Also, "N" in compost made of the same ingredients can vary , by how the compost is made. At high temperatures N will be lost, me thinks.
But as already mentioned, compost is not normally used for its nutrients value (as fertilizer) but as a soil amendment.

[ScottinAtlanta]

I use compost for its micronutrient values - the main ingredient is oak leaves.

[Worth1]

So then it would stand to reason there would be a difference in compost and composted.
Would composted chicken manure be compost?
If so it would be very high in nutrients.

Worth

[Gardeneer]

Originally Posted by Worth1

So then it would stand to reason there would be a difference in compost and composted.
Would composted chicken manure be compost?
If so it would be very high in nutrients.

Worth

Unless you make your own, what you buy in bags are mostly forest products, hay, straw, wood shaving, w/ some manure blended in. I know this true about cow/steer manures. Used to be you could get real manure.

Gardeneer