Does sheet mulch create it's own swale?

I want to create on contour beds of sheet mulch along a slight slope. Is there still an advantage to digging a swale in front of them or would the 12" or so of sheet mulch accomplish the same purpose?

If you were in a arid area I would say don't build any berms/raised bed even if it is only 12inches. If your area is prone to landslide and alot of heavy rains. I might also say that the 12inch berm (made of "sheet mulch") could be dangerous.

All that said assuming that you have a climate similar to me.  I would say that an actual swale would be best, with a 2ft depression that is 3ft wide, with an elevated berm that is similarly sized. But, just your 12inch of sheet mulch that will compost down to 2inch after 3yrs and erode down to 1inch in 5years is better than nothing.

S Bengi wrote:If you were in a arid area I would say don't build any berms/raised bed even if it is only 12inches. If your area is prone to landslide and alot of heavy rains. I might also say that the 12inch berm (made of "sheet mulch") could be dangerous.

All that said assuming that you have a climate similar to me.  I would say that an actual swale would be best, with a 2ft depression that is 3ft wide, with an elevated berm that is similarly sized. But, just your 12inch of sheet mulch that will compost down to 2inch after 3yrs and erode down to 1inch in 5years is better than nothing.

I am near Memphis, TN and we get a good amount of rain compared with most (50"+ annually, I believe).

One of my ignorant concerns was whether plants placed 12" above grade on sheetmulch would be able to access water at or below grade for a while. I guess the roots will reach and not find it hard to make it through the bulk materials, which will hold their own water from rain. Any added thoughts?

Also, I have never heard whether the end goal of sheetmulch is to see it compost down, at which point it's established and doing well. I had thought of doing composting in place. I guess you only need to do that a time or two in any given place before it's fine for a while / perpetually?

Tyler Upchurch wrote:Also, I have never heard whether the end goal of sheetmulch is to see it compost down, at which point it's established and doing well. I had thought of doing composting in place. I guess you only need to do that a time or two in any given place before it's fine for a while / perpetually?

It is my understanding that sheet mulching, depending on what is used is to mimics the natural soil-building process the way Mother Nature does it.

Depending on what material you will be using to do the sheet mulching will vary the results.

Will you use a layer of green or brown mulch, then cardboard or newspaper?

To me, the more green and/or brown mulch will end with better soil conditions.

The 12" that I saw mentioned will most likely kill anything that is growing.

One of my ignorant concerns was whether plants placed 12" above grade on sheetmulch would be able to access water at or below grade for a while. I guess the roots will reach and not find it hard to make it through the bulk materials, which will hold their own water from rain. Any added thoughts?

You need to consider the over all plan. What is happening between the sheet mulched beds?   Hard packed path,  mowed grass, ground cover?  
Most sheet mulch plans do not put plants at the top of the mulch but at the grade level in finished compost so that the roots are in the soil that is being built by the mulch breaking down.
For examples:  My berry vines have a mowed between rows and are kept mulched with grass clippings.  My vegetable beds that are cross slope are leveled and mulched the width of the path and bed  with heavier mulch on the soil raked to the edge with plants transplanted into it.

Also, I have never heard whether the end goal of sheetmulch is to see it compost down, at which point it's established and doing well. I had thought of doing composting in place. I guess you only need to do that a time or two in any given place before it's fine for a while / perpetually?

Yes that is the goal.  Eventually you will have raised beds on contour with naturally developing swale paths in-between.