I think you'll get a lot of conflicting advice to these questions.

Part of the problem is that there are a lot of different definitions of finished compost and even humus.

Many people plant in lasagna gardens, where the compost isn't even started, much less finished. Others feel that you should let finished compost continue to age for several months before using it.

I usually hot compost, and figure it's "done" when it heats up, then cools down and stays cool for a while. I then sift it through 1/4 inch hardware cloth. Any pieces bigger than 1/4 inch go back into the compost. The exception to that is that I'll pile it on the garden at the end of the summer even if it isn't finished in order to make room in the bin for the garden debris.

I put it all on the surface, finished or unfinished. I used to turn it under, but I'm trying the no-till approach to see how well it works.

As for the NPK question, if you apply 10 lbs of 1-1-1, you get the same amount of fertilizer as if you apply 1 lb of 10-10-10.

Your lucky day, whenever you put it on your soil it will finish without your help. Taking this way to serious.

Compost, if not well digested (finished), mixed into soil, tilled in, will cause the soil bacteria to get right to work on it and they will use a lot of Nitrogen while doing that and that Nitrogen will be temporarily unavailable to plants causing a Nitrogen deficiency in those plants.
Conpost, not completely finished, spread on the soil surface as a mulch will not cause the soil bacteria to get right to work on it and will not be a cause of Nitrogen deficiency if there is any.
So if your compost is not fully finished and yo uneed to take it out of the bin to make room for a new load, use it for mulch, not a soil amendment.

I've laid it on the surface, double dug it in, side dressed, planted directly in 1/2 finished compost without N problems.

My experience is the same as pablo's.

I use unfinished compost all the time as a mulching agent or in no-till raised beds.

Maybe we should clarify what goes into our compost....If one is composting meat, bones, fresh manure it might be different as to how "unfinished" one would use it versus just plant materials such as leaves and grass with some UCGs.

Lloyd

the one problem that can happen in unfinished, "immature" compost is phytotoxicity - it can give off compounds that inhibit seed germination in particular, and have other effects on certain sensitive plant species - the standard test for properly matured compost commercially is the 'GI' or germination index, to see how cress or radish seed [particularly sensitive] will germinate in it, high rate of germination = low phytotoxicity

the reaction of soil N to compost depends on it's composition - a high percentage of C in the compost [lots of woody material] can tie up N detrimentally if it's mixed into the root zone - compost that was a good balance of materials [like C:N about 25:1] will have little effect on soil N levels, and the microbes get to work converting the various organic nutrients into plant useable forms [not using N]

Bill

I have tomatoes growing in my compost bins. This always happens and they always taste fine. My general practice is to put it on the beds in whatever state it may be in the fall to empty and clean the bins, and if the raised beds shrink too much, give them more in the spring. Everyone that reads this will give you a different answer, and 99% of them will be right.

I agree with bpgreen, you'll get a lot of conflicting advice.

Bill, "squeeze", is right on.

Do you have pets that spend any time outside? If so, that can be an issue, if you're composting food or manure (dogs love manure). Mine ate it and then threw it up in the house (truly lovely) and some people have had dogs get very sick or even die.

However, I have used compost that still had recognizable bits in it in my plants in pots, and it has been fine. There is an issue with seeds sprouting from the compost, but the plants still loved it. My roses bloom 1 week after a good feeding like clock work.