Soils that dry out and become "hard as a brick" lack adequate amounts of organic matter, stones will not provide that and stones can absorb solar energy and heat up and cause more, faster evaporation of soil moisture. The spaces between those stones also allow accumulation of dust and organic material that can allow unwanted plant growth.

Otherwise stones could be a good choice.

kimmq is kimmsr

I would prefer wood chips or hay on top of the cardboard. Not only will stone make walking on this surface and moving a wheel barrow difficult but will allow for weed growth in between the stones. Stones will also forever get back into the garden beds.

You haven't said if this will be a row garden or not.

I also prefer to have my paths (walkways) a minimum of 4ft wide. As plants grow and bush out they will take up more of the path and by harvest time navigating will be difficult.

You are better off terracing the slope. That saves the most moisture. It can be done using the stones as retaining walls and as paths, if the stones are large enough. If terracing is not possible, consider making swales, with the paths on top of the swale. I make my paths using old carpet, wood chips in the paths are the worst possible solution, once they decay they make good soil - in the paths, with attendant weed explosion. I would use stones if they fit well enough that weeds will be strongly suppressed.

Then place as much organic matter in the beds. I have visited many italian vegetable gardens, and I am always shocked at the low quality of the soil. I appreciate that wood chips are hard to come by in Italy, that there are fines for not burning your yard clippings, and that mulch=mice. but you can go around and collect said clippings from people around you, grind them and layer them on your soil or better (to avoid mice) till them in. A chipper and a tiller are not expensive on the scale of your project. To kick the mice problem, place owl houses around the property.

The whole point of the wood chips is to improve the soil after they have served their purpose.

fwiw - roots from the desired plants do not go straight down in the bed or row they are in but will travel 4 to 10 feet out/down from where the stem enters the soil. It is at the tips of the roots that plants feed from (and where they should be watered also).

I have seen trees growing out of rocks and doubt that weeds will have any trouble doing the same.

You should be careful when bringing yard clippings home as they will often contain weed seeds. Hot composting them can reduce the seeds some but never seems to get them all.

Well,thanks for the comments, but apparently I wasn't clear: I have already mulched the paths with cardboard and wood chips,and worked in organic matter. My question was : can I put my large stepping stones on top of the cardboard/wood chip combo? and ,yes, I have already done some terracing,etc. And it's not a vegetable garden...

If you put the stepping stones on top of the cardboard and wood chips they may settle unevenly.

If that would be a problem, move the chips out of the way and place the stones, then rake the chips back around the stones.

It is all the sun and mild climate, Flora. The italian soils, like other mediterranean soils, have been cultivated for centuries and are degraded. Mulching can not be done, as I alluded earlier, because by law you have to burn your clippings, and also because voles are more pernicious there. No till agriculture is not used. And the hilly terrain increases erosion. Under olive trees, traditionally, people have tilled to destroy grass cover, in the belief that more nutrients will go to the trees.
People will add a bit of manure where possible but you will not see black soil.

Thank you, lazy_gardens. Glib, I don't know what you are talking about, I'm afraid. My soil's problem is that it hasn't been cultivated or cared for before. There is certainly no law here that one has to burn clippings! and thank Heaven, I've never had to deal with voles at all in the past 17 years in which I've been working here. I never see tilled soil under the olive trees ,and i am mulching...

Yes, large stepping stones will work fine. If you have problems, lift the stones and add more paper mulch before lowering them back into position.

Glib - I'm not sure where your information is from but I've been to Italy many times and seen many wonderful gardens, both ornamental and vegetable. Soil does not have to be black to be good soil and different gardening cultures have different methods.