Last year, I piled leaves, grass clippings and used coffee grounds about 4 feet deep on top of my garden. I didn't till them in, but tossed the pumpkins that had been used for decorations on top and just let them grow this spring.

Everything has pretty much rotted down by now.

I don't think you need to worry about adding too much. In my opinion, if you can till it in, it's not too much.

Agree - pile it all on and let it compost in place. Then till what's left in in the spring. Leaves that haven't been composed first, if tilled it, will bind up some of the nitrogen in the soil temporarily. Left on top they will decompose and insulate the soil, and keep down weeds, all at the same time. If you can shred them first - even better.

Dave

Never too much, especially if you're able to balance the greens and browns.

Wow, good to hear that I can use a ton of leaves.And yes, the leaves will be shredded. I have used a cover crop of winter rye the last two years. If I till in a balanced mix of leaves and grass clippings, can I still sow a cover crop in with it?

It is possible to add too much organic matter to any soil, look closely at any swamp and you will see that. However, in your yard and garden it is not very likely that you will be able to do that. You could either put the leaves on as a mulch, in which case no cover crop would be needed since the soil would be covered, or you could plant a cover crop, in which case you would not want to mulch since that could keep the cover crop from growing. Usually by the time the leaves do accumulate and you can till them in there is not enough time before the soil gets too cold for a cover crop seed to germinate, so it is one or the other.
Keeping in mind that tilling a lot of undigested organic matter into soil can cause the Soil Food Web to get busy and work on digesting that material that could well tie up necessary soil nutrients long enough so that any plants you want to grow will struggle to survive.

Ah, a swamp is a swamp because it has...wait for it.....too much moisture. The water is effective seal against oxygen reaching the bottom and the system becomes anaerobic.

If you till in a bunch and still have a bunch to mulch with, you can skip the cover crop and come spring you may be able to plant through the remaining mulch without tilling at all.

Winter rye is pretty, though, and I think it'll come up just as long as it's not actually freezing.

So, petalpatsy, why is a lake not also a swamp? A lake has a lot of moisture in it. A swamp is a lake that has too much organic matter in it.

There is simply no need ever to till, search all the results of lasagna mulch to see that it works fine on top.

I further believe that tilling places organic matter at a level in the soil removed from the organisms designed to begin the soil food web process.

"A swamp is a lake that has too much organic matter in it."

or it's a swamp, a naturally-occurring wetland that has nothing to do with the preferences or judgments of a johnny-come-lately species.

Swampiness isn't a problem for a swamp.

Kimmsr, -- seasonally flooded bottomland with more woody plants than a marsh and better drainage than a bog.

In the natural evolution of things, a lake is big and deep. There is enough depth that the water can stratify according to temperature, and no sunlight reached the bottom. Over time, with erosion and wind it will fill in and become smaller and shallower with more sloping banks. When sunlight can reach the bottom in seasonal low water levels, plants can sprout and grow. As vegetation cycles in a swamp, it sinks. Since the water isn't flowing appreciably, the organisms decay until the O2 is used up. Then the system is anaerobic, complete with methane bubbles.

If you removed all the organic matter, a swamp does not become a lake. Perhaps it could be called a shallow pond. But with sunlight reaching the bottom, the land will regrow plants. It's more a matter of depth.

A swamp is a swamp not because of dead added organics, but because it's shallow enough to grow plants and trees, and it's wet because it's got too much water flooding too often, and it's anaerobic because the water is not flowing.

Facts? We doan need no steenkin facts!

Thanks for all the input. However we did get a little "swamped" with added info.
I did want to make sure that I was going to be free from leaves that had not been broken down if I add too much. Or even if left on top and not tilled in, would they be just sitting there come spring? I can't imagine them breaking down in that fast a time. Even shredded.

Sorry mailman22. I'm a geek.

Pile those leaves on your garden this fall and leave them in place all winter to help protect your soil and then leave them there next spring to also protect your soil and help conserve soil moisture during the growing season, help control "weed" growth during the growing season, aid in keeping the soil temperature moderate which your plants will like much more than that really hot that soil left bare and exposed often gets which stresses the plants a lot, and as summer goes by the Soil Food Web will work that organic matter into the soil for you, better then you would ever be able to do with any kind of tiller.

I would suggest you shred those leaves if you want to see them decompose...ever. I get lots of oak leaves in my back yard and I can be raking out old, years old perfectly intact oak leaves for ever and ever and ever. Seriously, in August, I'll still find last autumn's oak leaves. But shredding them will get them decomposing and into the soil.

Last fall a neighbor brought over a 4 x 8 trailer loaded with, mostly Oak, leaves and we dumped that out on a section of the lawn that is pretty devoid of organic matter. I then raked those leaves out more so I had about 6 inch depth over a 30 x 60 area and then mulch mowed those leaves in and when done I had a nice brown soil with some green grass blades showing through. Then the earthworms started and there were tons of castings, and then this spring the grass in that are grew in greener, thicker, faster than just beyond the edge of where those leaves were. Today you cannot find a sign that such a large volume of leaves, predominately Oak, was ever there.
Yes you do need to shred leaves to get them digested fairly quickly, but if some tree species leaves lasted as long as some people think where out in the woods do these leaves go, or why are we not walking on piles of leaves several feet thick in the woods?

Kimmsr, I'm baffled that you had any area "devoid of organic matter" . . . .but then it's pretty amazing how many truckloads and trunkloads of leaves, straw, OPBGC, and Star$ imported here have been gobbled into the soil . . .gone, gone, gone. It's never too much.

Kimmsr,

My experience is that if I leave whole oak leaves on my flower/veg beds, they do not decompose. The woods and forests are a completely different environment. When I put whole autumn leaves in my wormbed, they disappear/change very rapidly. But not out on the beds. So to avoid raking year round, and to get a bit of good down into the soil of the flower and veg garden, I really do suggest shredding the leaves. At least my personal experience tells me so and that's why I have shared it.

Kimmsr--------cuticlesfromhell is right on target with shredding leaves.......they decompose so much faster that way! I got a leaf blower/vac/shredder at WM for $59 and it really works great! Neighbors know I'm crazy when I vaccume the lawn everyother day in the fall. Who cares--I'm a composter!!!!!and they just don't get it!