What I do to each bed in the fall is determined by what I intend to use each bed for in the spring. For example...if I plan to seed carrots, peas, plant potatoes or onion seedlings in very early spring I will incorporate the unfinished compost into those beds in the fall so they are ready to plant come spring. After incorporating the compost I will also cover the soil with an inch or 2 of shredded fall leaves that I can easily pull back or remove completely in the spring to plant seed.

If a bed will be planted with seedlings like Tomatoes, Peppers, Egg plant, etc. that don't get put out until the soil warms up a bit I will usually just put a couple inches of compost on top and either till it in a few weeks before planting or just leave what's left as a mulch for the plants.

Dig it in. But chop up the leaves first. If you don't, you'll be digging up whole leaves in the spring.

There is no one-way-works-for-all. Especially for leaves.

Your location, which you do not give, also makes a difference in how and when to use compost. Decomposition, benefits, and times/methods of application are greatly affected by climate. So a far northern gardener would use it very differently than a deep south gardener, a coastal gardener would use it differently than a high desert resident would, etc.

Plus are your gardens in ground or raised beds? That makes a big difference in soil residents activity if just spread on top. Exactly how "unfinished", how old is it? What is it primary composition?

Much more info please.

Dave

Appreciate the responses. More information:

Am in zone 7. Vegetables growing in the ground. Compost ingredients were fresh grass cuttings and leaves. Ratio was 1:1 (grass:leaves) when using shredded leaves, 1:2 when leaves were unshredded. By this time of the year, I usually have a significant amount of what I think is finished compost: black, "foresty" smell, somewhat crumbly, can't distinguish the individual components. Not so this time around. Good initial temps of 160 degrees but fell off quickly. Turning it had little effect. Built the piles in late May-early June. (Probably didn't protect it well enough from pretty heavy rains.)

Have calculated that I have enough to cover the garden with a 4"-5" layer of the unfinished compost and maybe another 3" of shredded leaves. Maybe these amounts are too small to make an appreciable difference...I don't know.

If digging them in (as opposed to spreading on top of the soil) will do a better job of improving the soil, I won't mind the effort. I need the exercise.

Seems to me if you leave it on top, you might get some composting of the layer underneath, but not a lot on top. So you end up with a bed ready for planting in the spring that has uncomposted material laying on top. I'm not sure why you wouldn't want to dig it in, though it certainly is a lot of work. As long as it is mixed with soil, especially with a 1:1 mix of green and brown, it should in situ compost nicely over the winter. In zone 7, I suspect you're not fighting any permafrost. I think that half a foot of organics is going to make a big difference if mixed to spade depth.

As stated above, there is no one single way. But ideas can be helpful, so here's my way. I grow in raised beds. When I need compost, but have none finished, I lay 3-6 inches of the rough, chopped stuff right over the soil and then cover it completely with mulch (pine straw is my default mulch but I have also used leaves, chopped). In two or three weeks, it is totally broken down and I am ready to plant. I often do this in late winter as I am getting ready for spring planting. I should also say that I never put grass clippings or weeds of any kind into my pile. I am not always consistent in turning my pile and I don't trust them to get hot enough to kill out weeds. I don't mind at all the surprise tomatoes, flowers, etc. that come up in my beds. Those, I often transplant to other areas of the yard.

Way too much compost. 50 cubic yards per acre is the best amount of compost to add per year and that is less than an inch thick over soil. You may have reduced plant growth next year if you add all the amount planned.

Many will disagree with a research based recommendation because of the thought that you can never have too much organic matter. The problem is that you are drastically affecting soil pH and nutrient availability when you add high levels of organic matter. Having only partial composting is far worse.

"The problem is that you are drastically affecting soil pH and nutrient availability when you add high levels of organic matter. "

Very true but whether that drastic effect is a negative or a positive all depends on the soil pH, soil type/make-up, effect on plant growth, and nutrient availability to begin with. Only way to know that is with a professional soil test first.

As an example, my native soil is very alkaline with a pH well above 8+ and is quite coarse and rocky. I routinely added 2-3" of fresh compost (tilled in) each spring and fall and use it to side-dress and mulch with throughout the season. Have done so for many years with excellent results as it lowers my pH and improves the soil tilth. But my compost is a 5 part mixture of grass/hay, fall shredded leaves, kitchen and garden scrapes, coffee grounds, and approx. 1/4-1/3 animal manures. So it cooks fast and hot.

My primary concern with what you have described is its very limited components. With yours and without knowing your pH and/or tilth I'd be inclined to till in only a couple of inches of it this fall and let the rest keep on cooking till spring and then add another 1-2" then 6 weeks before planting. I would NOT add the 3" of shredded leaves but would mix them in with the remaining unfinished compost and leave until spring.

JMO

Dave

Thanks much for the comments and advice ... and sharing your experiences.

Again what I have is unfinished compost. Barrie, in past years (when my composting was successful), the original materials I put into my 3' tall wire bins composted down to about 12" of finished compost. Wouldn't the same possibly happen if I spread/dug in maybe 3"-4" of unfinished stuff ... it would end up being an inch or so of finished compost? Would that be in the accepted range? Just wondering...