Interesting to read how in English it says "advocates claim that the technique helps to improve soil fertility, water retention, and soil warming" while in Spanish, instead, it gives it for granted ("Este proceso mejora la retención de agua del suelo, aumenta su temperatura y su fertilidad...").
I practice a lazy form of this: I live on the edge of a small forest, what remains of what used to be here as this town was built and grew up around it, only about 100 feet deep at widest.
I came back with a lot of wood of fallen trees, branches, and filled about a foot, to save costs on soil (a mix of coconut coir and Canadian peat; similar to a potting mix in a lot of ways). I only need to water when its supremely dry, which happens up here during the peak (and hottest) of the summer.
I live in Maine, summer is also fire season, and people coming up here (because we're the "vacation state") love to start their little dumbass campfires because they want to play their stupid little "roughing it" fantasies; when its like that, I water.
Now, the peppers and tomatoes I grow? They eat all the water I can give them, and their pots aren't rigged with hugelkulture-like techniques. Maybe I should have.
Solid wood that has been buried can take 20-50 years to decompose, depending on species and the thickness of the wood.
If you know you are going to die of old age in your current home, and you haven’t hit your fifth decade yet, solid trunks or thick branches are fine.
If you only have 2-4 decades of life left, consider thinner branches, or chip the wood into rough pieces that max out at about the size of a paperback (large trailer-towed chipper for wood up to 24″ in size, the kind most Arborists use).
If you are old enough to retire, I would strongly recommend chipping as fine as pieces no larger than a credit card. Which is about the size that any landscaping supply place would have.
If your place is not going to be permanent (you have plans of moving within the next 5-15) or you really are quite elderly, I would recommend avoiding wood entirely to go for sawdust, leaves, and even entire bales of hay that have not been torn apart (still compressed, just remove the polyester bailing rope). If you have access to herbicide-free grass clippings (orchard, etc.), I would also strongly recommend composting that over a few months and then using that as a thick final layer (about 5-15cm) before you pile the soil on top.
I don’t use Hügelkultur to make mounds, but all of my custom, home-made planter boxes have it as their primary feature: a good 40cm of rough wood chips (that go about 10-15cm down below the surrounding ground level), 30cm of compacted hay from bales, a thick 10cm layer of composted grass clippings, then 10-15cm of fine topsoil. It has compacted by about 15cm over the last year, and I expect it to compact a little more. I pulled some soil off this spring and added another layer of grass clippings before putting that soil back and adding another 10cm of fresh soil on top. We typically find the surface layered with worm castings after a good rain or watering, which is a sign that things are working well.
If you are in a typically hot or arid area, I would also strongly recommend looking into the Ruth Stout method for weed suppression and moisture retention. I use about 10cm of my composted grass clippings and another 20-30cm of fluffed hay from bales on top of that, and it does wonders for the garden - we watered only about 20% as much as our neighbours and had almost no weeds in the covered areas. The soil remained moist and super-soft all year long.
Leave that cover in place and add another 20-30cm in the fall time for the following year, or use a garden spade in the fall to gently move the current year’s cover into the upper layers of soil for beneficial bugs to winter down in before refreshing the surface with another full 30-40cm layer. It will compact over the winter, and you plant in the spring directly through the hay. Things like garlic don’t even need to be buried - you just put them directly on the soil and close up the hole you made in the hay.
Aren't they saying the opposite? I think the point is to buy materials that will last so long that you won't need to replace them in your lifetime (or before you move house). But I'm not sure I'm reading it right.
