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mcnattyp

Minimal cost, maximum results for large-scale sheet mulching

mcnattyp
15 years ago

I'm in Portland, Oregon.

I've just acquired rights to garden an empty lot across the street and need to rehab the soil as much as possible before the coming growing season.

It's a 50x100 foot lot, so 5000 square feet, which ~ 1/10th acre. It has never had a house on it, and is flat. It has a combination of bare dirt and weedy grass, along with the requisite dumped junk.

I'll be doing soil testing to ensure I'm not planting where anyone's parked an oil-leaky car, but I've checked with some long-term neighbors and it seems like a pretty clean lot, so worthy of my time investment.

My first goal is to improve the soil. The ground is very hard packed, but good quality Willamette valley soil. It just needs a lot of humus.

With smaller garden spaces, I would know how to handle this. But I've never done such a large-scale soil rehab. I think I'd like to do sheet mulching, but I'm trying to figure out the most cost-effective and efficient way to get the whole thing covered.

Cardboard and newspaper I can do via recycling bins at malls and grocery stores.

What else should I use? Buying enough compost from bulk soil places would be over $500 for an inch coverage. I can get leaf compost for about half that much. I could try to source animal manure, probably for cheap, but it would require multiple trips to get enough. (I have a big truck and trailer to haul.) And I don't know much about animal manure in sheet mulching. (I.e. time to decompose, animal type.)

And of course, I can get wood chips from the local power company for free.

Assuming I use the free & easy cardboard and wood chips, what else should I use for maximum efficiency of my sheet mulching endeavor? How deep is the minimum I should go? (I know that more is always better and it settles down a lot, but I doubt I could cheaply source enough combined yardage for 12" of sheet mulching.)

As an alternate plan (or possibly complimentary plan), I've thought about planting ryegrass/austrian-peas as an overwintering cover crop. If so, I would till them in come spring, possibly with some amendments.

But it would be ideal to do both - sheet mulch AND cover crop. Can the cover crop seeds get sown into the top of the sheet mulch, to get tilled in later?

And finally, I'm not afraid of tilling the whole thing, once. Tilling in 2 inches of compost is an option I've considered, but would be costly for the compost purchase price.

I know this is not a science, so I'm looking for opinions about my specific situation.

Comments (9)

  • mcnattyp
    Original Author
    15 years ago

    Let me also add that one option would be "food wastes" from the City of Portland' restaurant/food-service composting containers. I had thought about regular trips to New Season's (grocery store) as well as local restaurants, and asking to have their compostables. I've investigated a few restaurants' bins and it seems heavy on paper napkins, with lot of food bits.

    If I used that product, it would be uncomposted, fresh. I don't know if that's a good idea in sheet mulching, but it is an option for potentially large quantities of organic matter.

  • wayne_5 zone 6a Central Indiana
    15 years ago

    Is the whole lot going into full production next year? If not, stips or portions could have an extra year to build up.

  • digdirt2
    15 years ago

    I'd agree with Wayne, do it in strips or chunks at a time and used the unimproved strips for walkways next year. End of that season the soil beneath them will be better and you can turn it over onto the unimproved strips and go to work on them. Good soil improvement takes time so there is no way you can do it all and get ready for next season but within 3 years you'd should be in good shape.

    With that approach you can use all the items you list, even the green manure plantings, and anything else you can get your hands on - straw or hay bales, bags of leaves, grass clippings, can you get seaweed?, manure, the stuff from the grocery store, etc. Basically anything that can go into a compost pile can go into sheet composting so check out all the "What have you fed your compost?" discussions here for ideas.

    Good luck.

    Dave

  • mcnattyp
    Original Author
    15 years ago

    After putting some more thought into it, and checking out the lot with a permacultural friend of mine, it seems likely that I'll focus on smaller portions both to grow and to mulch. He's made some suggestions about locally sourced free fresh leaves delivered by the dozen-yard, free wood chips, free fresh horse manure, and free cardboard, all in large quantities. With those four products, I should get good results in time.

    And I'll organize just a portion of the lot for spring growing, and perform a different mulching possibly with some tilling.

  • terrene
    15 years ago

    I've been creating 2 native "meadow gardens" in a wild area in the back 1/2 acre of my yard. This area was colonized by lots of invasive plants such as Oriental bittersweet, Buckthorn, shrub Honeysuckle, etc, some of which were quite large. I cut the larger shrubbery/small trees, but wasn't sure what to do with all the leftover stumps and zillions of seedlings and weeds.

    I considered tilling, hand digging, etc. but sheet composting seemed to be the easiest way to create a garden under these conditions (maybe most all conditions). All summer, I collected bags of grass clippings at the town compost site, along with extra paper leaf bags. I would tear open and spread the paper bags, right on top of the weedy stuff (mowed or not), then spread 2-3 inches of grass clippings on top. As this decayed, I added more clippings or leaves or whatever, right on top.

    This has worked well so far. Grass clippings are particularly well-suited for this purpose. When they get wet, they congeal together, to form a nice thick mat that is very difficult for weeds to penetrate, even after the paper breaks down. This thick layer also deprives the stumps of light, which prevents them from resprouting, without the need to use herbicides (I hope). A note: fresh grass clippings stink pretty bad until they dry out!

    So far I've covered approx. 500-600 SF between the two gardens. Cost: $0 (except if you count gas required to drive 4 miles each way to compost site). These gardens will easily be 1000 SF or more when finished, probably a 3rd garden added. I started planting this summer but expect by next Spring, I'll be able to dig holes and plop seedlings much more easily.

    Here's a pic of the sheet composting in process - this is a new layer, in the background right are older layers, where I've added leaves/compost on top. You can see how terribly weedy this area is around the edges.

    {{gwi:316184}}

  • paddykevin
    15 years ago

    I think you have an additional item of concern here, and that is of aesthetics. I can imagine a neighborhood uproar if things are not done in an attractive manner. If you go the food scrap route you will get credit for any and all vermin in the area, linked to your efforts or not.

    Are you in this for the long haul, a couple of seasons, or just the next year? My thought is that perhaps the interbay mode of attack in a sort of raised bed, maybe just made out of logs, with wood chips over the burlap? The log bins could be perhaps one or two logs or branches high, reaching a total height of say one foot, and put together in a Lincoln Logs sort of manner

  • Kimmsr
    15 years ago

    Concentrating on many small plots, as in Square Foot Gardening, would be much easier to make work than that whole 5,000 square feet of garden. Planting a cover crop may well involve tilling that whole area while mulching many small planting beds would not, therefore less work and better for the soil. If you can get leaf mold you should also be able to get leaves from deciduous trees, unless everyone around you hires lawn care people to haul them away.

  • theaceofspades
    15 years ago

    First I would clean up any rocks junk metal debris on the ground. Cut or mow everything down. Rake the weeds and brush into a compost pile or shred if you have one, works better. Roto till the entire plot, remove again the unwanted debris. Spread free town compost on the ground and roto till in. I tilled in compost till it looked good. You can then plant asparagus, horseradish, rhubarb, herbs etc. Plant a cover crop while the compost breaks down and to hold down weeds. In spring, I lay a heavy 6% filter cloth over the single plant vegetable garden area. This leaves me to weed only the row vegetables, carrots, beets, kohlorabi. Tilling in compost gets you planted ASAP. Sheet mulching would take a year or more to finish and still leave the original ground compacted and full of debris, if you decide not to till.

  • token28001
    15 years ago

    Our landfill offers free leaf mulch all summer long. You just have to have a truck or a trailer to pick it up. Renting a truck isn't very expensive.