I've never had an over fertilization problem from finished compost and other posters here have said that compost is generally low in nutrients for the most part, it mainly adds organic material to the soil when used as a mulch. That said I don't add urine to my piles but do add chicken poop which by bulk is about 1% of the materials added. Main ingredients are grass clipping, saved autumn leaves, kitchen scraps, and garden waste.

The issue with not having the 'usual' mix of nitrogen to other stuff is that it tends to not compost well and go anaerobic and smelly. If you want less nitrogen in your compost, let it age longer, nitrogen will tend to volatilise, off-gas and otherwise leave your compost. The numbers you sometimes see about what is high in nitrogen is what goes in the compost pile, not what comes out. Most studies I've seen say 'finished' compost has a modest amount of nitrogen, i.e. unlikely to be so concentrated or excessive when added to soil to really cause problems, and also tends to be in slower-release forms as in humus - although may differ, YMMV (and perceptions of 'finished' may differ, too).

Finally, I think the mantra that's often repeated here that compost is a soil amendment, not fertilizer. Benefits are more about adding organic material, organic life and structure to soil - the 'macronutrients' aspect is a secondary benefit.

(A more informed science-type person would also point out that I think K and P added in form of compost tends to accumulate over time, i.e. not as volatile/subject to washing out as N, but I'm not science-y enough to be sure about when this becomes relevant, I think only when lots of compost over many years. Anyway adding compost will help some in these areas, but again, not as concentrated as a fertilizer would be)

So I'd make compost whatever way works for you and add finished form to your soil to get it in good condition, and after that see what you need to do to improve. Specific plants/conditions may need a bit more care of course.

IMO, YMMV, etc.

I had written a response to this earlier, but apparently it has vanished :-))

Previous comments are on point. Compost is NOT a fertilizer. The nutrient load is very low - generally something like 1.0-1.0-1.0, give or take - and it just does not have the ability to reliably produce nutrients in the concentrations necessary to maintain healthy plant growth solely from this source. That's why it never comes with an NPK ratio on the bag or displayed at bulk soil yards where you can purchase :-)) Of course this would be the same for any compost you made at home as well, regardless of ingredients. There ARE a lot of benefits to its usage, but being a fertilizer or supplying specific nutrients in a reliable manner is not one of them. Look at it rather as supplementing the natural soil fertility.

If you have the need to add specific nutrients to your garden, don't look for compost to supply them. Instead, you should get a proper fertilizer to address those specific needs.

But unless you have a professional soil test done, there is really no way you have of evaluating whether or not you need to add any specific nutrients at all.

I agree with @gardengal48 (PNW Z8/9) We bought a soil testing thing on Amazon and found it interesting how different the soil is in various areas of our property. I'm sure if you test your compost, it won't have many nutrients in it. We put worm castings from our little worm farm, in ours along with the usual, but we always test and fertilize according to the needs of each veggie and tree, and it has helped our sad situation immensely.

The thing that triggered the test was the sick looking Persimmon tree. I REALLY want olives this year, and we discovered that if there aren't enough nutrients, the tree will drop fruit in favor of leaves. We found that both trees were seriously lacking certain nutrients, so hubby purchased fertilizer balanced to correct those issues. Now, we always test before putting in new plantings. Peace of mind.

Let me add one thing about compost as fertilizer. The NPK of compost is quite low. So per unit volume of compost, compost has low nutrient value. BUT, when we use compost, we usually use HUGE amounts of it. So, in principle, the nutrient value of heavily applied compost can be substantial. BUT, the nutrients in compost are in the form of organics (lignins, etc.) that don't break down readily. So those nutrients are released very slowly, as those organics degrade. The point being that compost is a very poor "right-now" fertilizer. In fact, most organic fertilizers are that way as well. So the word "fertilizer" is somewhat ambiguous. Depends on how immediately you want fertilization action. I don't regard compost as a fertilizer because, when I apply it, it isn't fertilizing anyone.

Just an FYI, but home soil nutrient testing kits are generally a waste of money. They are notoriously inaccurate. If you want to find out the nutrient load of your soil, have a professional soil test done. They will give an accurate reading and recommend specific nutrient additions in the quantities necessary to produce healthy plant growth. They also evaluate the trace elements or micronutrients that a home test kit is not able to measure. Many of these can be just as limiting to proper plant growth as the primary 3 macronutrients.

@gardengal48 (PNW Z8/9) I figured you were going to say that, but with 1.5 acres of rocky hillside that has been owned by 3 different families and has plantings 30 years old, all on different elevations, it's all different, and we just can't afford to get so many soil tests.

You will be happy to know, the persimmons look very healthy now, and the olive trees actually didn't drop their olives.

Nutrient needs not only vary by plant but by soil (as already mentioned) and time of year. I don't think it's feasible to make specialized composts. Too many variables.

I liked daninthedirt's post about compost not being a nutrient source per pound but we use tons of it. I can attest. My vegetable beds are so high in P from 25 years of compost addition that I had to cut back to keep it from getting excessive. But when I bought the place, I planted fruit trees that wouldn't even bloom until I added P, so I know it was real low.

I thought it was an odd question at first until I thought about it some more and realize that I already pretty much do what you are talking about. I have general compost that I will throw any and all garden and kitchen refuse in. But then I also have bottomless garbage cans that I make leaf mold in. Obviously the latter will have a lower nitrogen content than the former and I do use them at different times for different things.

And I also have a smaller covered bin that I use to store finished compost that I have sifted, to which I will often add another healthy helping of grass clippings or alfalfa pellets to up the nitrogen content a little more. Allowing it to sit for a bit to finish "digesting" the added ingredients before using.

That said, I agree with the others though that compost in any form contains a relatively low dose of quickly available nutrients and it is difficult to overdose with it.

Rodney