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Question for ya: I started a sheet mulch garden some months ago and now the level is down lower than I want. I put down layers of dry and green material, then made holes in that, then placed soil in, then planted in that. There are a lotta plants in there that I'm still harvesting from. What do others do when the bed height is lower than they want? Do you do the whole thing over again, covering the plants? Surely not! I could but would much rather not. We've been getting a good bit of rain here in Southern Thailand, and the rainy season hasn't even really started up yet. It'll get down to original ground if I don't build it up again. I could use the original soil, which might be decently good soil actually, but I'm doing this as part of a master's degree, and want to use a sheet mulch bed.

I'd love to say that I've been keeping detailed records, but I haven't been. I'm doing agricultural development research, not agriculture research, so, detailed records are not all that important, and, I'm terrible at keeping records!
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IMO, sheet mulched beds shouldnt be just a make it once and then its done forever - kind of thing.
you keep adding to them slowly, every few months (ideally but it does get easy to procrastinate), a new layer of mulch/leaves/woodchips/yard trimming/finished compost/etc etc etc...on top.

many established perennials dont want to have the base of their trunk covered up, so it can be a bit tricky....not to bury them too deep.
then again, some love it, you can keep burying their roots each time you mulch, and some will even layer themselves underground, create suckers and like to have soil/mulch mounded on top of the trunk...
so it depends on what established plants/trees you have...how to go about adding mulch to the top, and not burying the established planting, or burying them if its that kind of plant. blueberries, fuschia, figs, a lot of bulbs...theres tons more...but these are some that i can think of quickly that you can just keep burying them with the new layers of mulch. most fruit trees though, dont like it, although if you just make thin layers its ok. i guess thats a way to go, just keep adding thin layers, and thinnest around the base of any established plantings. well my beds are often lumpy, i find that lumpy and not perfectly level beds work better, so i just sort of sculpt a new layer on, when i keep adding to it...but i dont know how to explain that....

also something thats really great about sheet mulch/any kind of mulch, is its not just that you create that great soil above your native soil, but the native soil underneath becomes improved.

Thanks Leila ... ) I've got annual vegetables (mostly kale and Chinese cabbage) so I don't want to bury them. I don't cut the plants, I just harvest the bottom leaves. Not sure how I'll do this. I'm guessing the easy way isn't the most convenient way for me. I'll figure something out ... thanks a ton )

Troy Santos wrote:Thanks Leila ... ) I've got annual vegetables (mostly kale and Chinese cabbage) so I don't want to bury them. I don't cut the plants, I just harvest the bottom leaves. Not sure how I'll do this. I'm guessing the easy way isn't the most convenient way for me. I'll figure something out ... thanks a ton )

cabbage and kale can be "layered" or more plainly, buried under soil.
they tend to get these long stalks eventually, and kinda top heavy and some all curly shaped and awkward (they are usually perennial ish here).
you can (dont have to obviously) bury them deeply, you can also push them over, make a little trench for where they lay downward, then hold down with rock or just bury them under soil/mulch. then they will shoot up a ton of new growth...like each branch almost becomes a whole new plant. but they will never make proper heads that way, just little mini tiny heads. which are just as yummy....

yeah its kinda strange to just throw mulch/straw/soil on top of plants like that, but it works well with some, including kale. i also throw lots of mulch on stuff like strawberries (to the point where a lot of the leaves arent even visable!) or completely cover a potato plant...say just some examples of plants i do this with. they pop right back up above the new top layer in a few days....

troy, I mow the weeds and lawn, and empty those lawnmower baskets onto the beds. I've had neighbors drop off bags of their lawn cuttings, and I've collected neighbors' leaves and bags as well. The small pieces that the lawnmower creates are just right for tucking around the plants that are already in the mulch. You can leave a little space around the stalks of the plant, build it up on the sides, like the shape of a funnel, just so that most of the roots and soil are covered with thick mulch. But like Leila says, you can almost bury most of them, and they love it.

I would watch out for the sow bugs, rolly polly bugs that love to be under the mulch. They might chew on a really buried stalk or some leaves.

The mulch will keep breaking down and dropping, so any new layers you put won't stay that high for long. But it is so, so worth it.

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Awright Leila ... I can try burying the kale. I know that kale will send out new shoots after you cut the stalk, so ... okay they'll rise from the dead after being buried! The Chinese cabbage (the loose-leaf kind, that doesn't head, and not cabbage) surely won't survive, and that's okay because the snails are making too many holes. I tried crushing egg shells and putting that around the bed, but it hasn't worked. Seems I'm supposed to blend the shells up in a blender, but I haven't tried that yet.
And Cristo ... seems like you don't add soil to the new layers. Adding new mulch seems easy enough, but to also add soil ... this seems easier. The material that I spread is fairly fine stuff. Lotta grass cuttings and small leaves. It all comes from the university where I live and study. Seems I could make a funnel kind of shape around plants easily enough. So, it looks like I've got two ideas to play with here
Any opinions about auto emissions getting onto the grass and leaves long before they get to the garden? I'm doing some applied research in urban gardening. One reason I want to use raised beds in my research is to avoid contaminants in polluted soil. But, if the components of the bed are contaminated as well ...! I don't know what particular contaminants are in the soil or in the grass and mulch here, but it's likely that whatever is coming out of the tailpipes is what's on the grass and leaves that I use for this sheet mulch bed.
I've read research that says humus in soil stores lead (and maybe other contaminants) so plants don't take up these things. The matters of soil contamination and remediation are tricky. So is the matter of how much an individual can tolerate a so-called toxin, depending on a whole slew of factors. Not trying to pin all this down ... way too complicated. But, yeah, I'm interested if anyone has ideas about this stuff. Ingesting these things is a serious health concern.
On that note ...
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troy, no, you don't need new soil. The organic mulch layers will improve the soil you've got.

As far as contaminants in an urban setting, you might look into diesel vehicles, (like trucks, UPS/FedEx trucks) because diesel settles to the ground. Whereas passenger vehicles use unleaded gas, and have pollution controls, so what comes out of them mostly goes into the atmosphere. Motorcycles do not have pollution controls, so what it all is and where all of it goes, I don't know. Different states have different pollution requirements, and different counties in each state have different pollution requirements for what comes out of a tailpipe.

But what is more of an issue is using cuttings from a commercial place, or even a residential place that uses pesticides and herbicides, like the university, like a City park. Those contaminants are in organic mulch from those places. The rules/law regarding using those things, to make them safe, are in the Organic Certification rules.

These are a few of the things to research.

Thanks a lot Cristo. That's really encouraging. I don't need new soil! Of course I'll have to add often enough to keep the height somewhat stable. Something to toy with. And thanks ... for the link to Rich Soil Ah ... now I see. That link to Rich Soil was an add. I wondered why there's no username with that "post"!

I didn't give you any links. Must have been something this website does.

Yeah yeah. You see that little smoking house at the bottom left? When I posted my last response, the little blurb said, "I completely agree with you. Have you had a look at [Rich Soil URL]?" I noticed out of the corner of my eye, later on, that the little horse buggy wheel says AD. But when I really look at the wheel, the word AD isn't so obvious. Anyway, that's what I meant.

I really don't like these sort of tricks of the marketing / capitalism trade. I realize that we all need to make a few bucks, but when it's done in a way that tricks people, or manipulates people .... What's the opposite of "a warm and fuzzy"?