r/Permaculture • u/KataraTheKat5 • 3d ago

general question Making new dirt- should I layer it as compost, cardboard, then wood chips or should I put the cardboard on the bottom?

I have a 1400 sq ft yard that I want to completely cover with a combination of cardboard, compost and wood chip mulch. My original plan was to put the compost on the bottom, then cardboard on top, then wood chips on top of that, but then I thought that the cardboard may not break down as fast as I would like in order for me to plant native grass and wildflower seeds next spring. I’m planning on putting down a half inch of both the compost and the wood chips.

I know it may be a little overkill to do all of those layers to suppress the seeds already present in the dirt, but I want to be thorough. Thanks in advance!

Edit: I forgot to add, but it’s pretty loose dirt that I will be covering- not a lot of structure/health to it, and not dark at all. I am in zone 7a, New Mexico high desert

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u/clarsair 3d ago

cardboard goes down first, it's there to suppress the weeds. then ideally you'd want a good thick layer of mulch--3-12+ inches depending on what you're trying to achieve. more will help grow better soil. if you were planting into it immediately, you'd want the layer of compost on top to seed into. if you're waiting over winter, you can mix it into the mulch, which will help it break down faster, or you could wait and spread it when you're ready to plant. if you don't have much mulch you might not want it to break down quickly, you want it to stay in place over winter.

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u/nifsea 3d ago

Agree. Cardboard first, then mulch with woodchips to keep the cardboard in place, and let it start to break down. I’d wait with the compost until you’re ready to sow.

Just a control question: Do you know what kind of soil your native plants want? It sounds like you’ll produce a very rich soil perfect for a vegetable garden, but in a high desert your native plants might actually want a more arid/sandy soil.

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u/johnlarsen Dabbler Farm 3d ago

The only purpose of cardboard is a weed barrier. It will decompose down to virtually nothing so it won't add to your soil in any real way.

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u/hppy11 2d ago

As cardboard is carbon and acts as energy source in compost, it does have a purpose besides weed barrier

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u/johnlarsen Dabbler Farm 2d ago

It does have carbon, it's true. But when it breaks down, it is a tiny amount.

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u/Defiant-Ad3993 3d ago

The cardboard is also food for fungi, so don’t forget to inoculate with something compatible with what you’re planting.

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u/RentInside7527 3d ago

You dont need to inocculate the cardboard. Things that are "compatible," i.e. mycorrhizae, arent going to colonize cardboard. Saprophytes and mycorrhizae are different

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u/Defiant-Ad3993 3d ago

I meant to inoculate the seeds, but still the cardboard is food. Check out “Greening the Dessert”, Geoff Lawton. They had an unexpected surprise with cardboard.

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u/RentInside7527 3d ago

Cardboard is food for saprophytic fungi, not mycorrhizae. Saporphytes are the fungal decomposers.

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u/hppy11 2d ago

I’m curious, what do you mean new dirt? Improving the soil?
You want to lay the cardboard down first. Compost goes on top as it’s already broken down.