Sheet Mulching on Steroids

Browsing YouTube today, I came across an interesting video. These guys take sheet mulching to a whole new level. I didn't keep count, but this bed has at least a dozen layers in it. What would be the advantages/disadvantages to all this extra effort?

Woah lol. I'm not sure if that should be sheet mulching on steroids or hugelkultur on crack. I'd say the advantage is that it breaks down into soil very quickly, which could also be a disadvantage vs hugelkultur. I don't think there's much advantage vs regular sheet mulching, since you generally use sheet mulching to cover larger areas anyway, you don't really want it 3 feet high, or at least it isn't very practical.

The video kept buffering and I couldn't be bothered with it, but technical stuff aside, I got all excited by the 'New Zealand' bit, but all the accents I heard were all from other countries

What I took away from this video was:

Wet the cardboard before putting it down to make sure it's soaked through and not just wet on the surface.

He added worms that he had harvested, and he added them early, burying them under a lot of material before he was done. I was surprised by this.

He also added some things that aren't normally mentioned in sheet mulching, like gravel and clay. After a while, I started to get the impression he was just padding the video by finding more things to add.

So I watched the video again and took notes. His layers were, in order:

cardboard

green weed clippings

kitchen scraps

soil with worms

topsoil

dried hay

grass clippings

soil/compost mix

crushed rock (very sparingly)

clay soil

dried grass clippings

dry leaves

soil/compost mix

straw

That's 14 layers. I'm sure when it all breaks down this will be an incredibly fertile and bioactive bed, but it seems like overkill to me.

Sounds to me like a really large, yet "flat", compost bin :p "composting in place" sounds like a great idea. Assuming it will be a year or two before garden veggies are grown there.

He actually planted in it right away. He said at the end that if you are building a bed in the fall to mature over winter, you should add more nitrogenous (green) material than he did.

is this the same as lasagne gardening? that is what it looked like to me.

Yes, sheet mulching and lasagna gardening are two terms for the same thing. Usually it's done with a lot fewer layers than this.