The Walden Effect: Farming, simple living, permaculture, and invention.

Cardboard lessons

Storing cardboardI hardly know where to start telling you the story of the cardboard motherlode.  Mark was the one who found it, even though we were both in the same room.  My husband has developed quite a knack for ferreting out biomass going to waste, so when our friends told us that they were bringing a lot of cardboard boxes to the recycling center, Mark's ears perked right up.

The story is a bittersweet one of composting old dreams, and made me feel very lucky that we'd started our microbusiness and writing ventures in the era of the internet.  The owner of the unwanted boxes is a writer who had gone the semi-traditional self-publishing route decades ago.  He ordered thousands of copies of his books, enough to make it worthwhile to get them printed, then a big truckload of cardboard boxes to use when mailing the texts to customers.

Rotting cardboardAt that time, it wasn't really possible to follow my microbusiness admonition to keep your startup costs below $1,000 and not to fill your barn with inventory, nor could our friend easily sell his books to a worldwide market at no cost (except a per-book fee) on Amazon.  I suspect he also didn't really need the cash, and liked writing more than he liked marketing his works --- having to go get a job in Kingsport if our microbusinesses fail is a strong incentive to keep our noses to the grindstone.

So the books sat in our friend's office and the boxes moldered in his barn until Mark heard about their planned journey to the recycler.  The books were already gone, but three huge bales of cardboard boxes were free for the taking.  They'd been sitting on the ground for years and some had lost as much as half their mass into the soil, but most were perfect kill mulch material.

Stored biomassSome of the partially degraded boxes had mycelium growing on them, which just supports my hypothesis that corrugated cardboard is like candy for soil microorganisms.  I've been wondering lately whether Steve Solomon is right to say that the glue is what makes cardboard so enticing, or whether the answer is much simpler.  Could the corrugations give just the right amount of air space to keep the cardboard moist but still well aerated, creating the perfect environment for fungal growth?

We've stockpiled the cardboard with the straw at our parking area and I carry in a big duffel bag full each time I walk Lucy.  I'd like to say the cardboard will feed my garden forever, but I figure it might last...two weeks?

Our chicken waterer is the POOP-free alternative to traditional, filthy waterers.

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.

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Cardboard is usually made with a starch-based glue. I guess molds and critters like their carbohydrates. :-)

Comment by Roland_Smith Mon Mar 19 15:54:57 2012

I read about kill mulching form you all the time, but lately I've had an unanswered question. I used kill mulching around some tomato starts a couple of years back and found that it retained way too much moisture and contributed to the plants stunting. I live in the Pacific Northwest, so there's lots of rain over here, and I was wondering if there's such a thing as mulching too early? Should I be waiting for a specific soil temperature or weather before I go covering up the ground? And yes, I left breathing room around the base of the plants, but maybe what I thought was enough breathing room isn't? Do you have problems with weeds around the bases of plants? And do you have any recommendations on how to find free cardboard when you don't really have friends (therefore lucky caches aren't available).

Wow, lots of questions, sorry! Just want to succeed so badly this year!

Comment by Brandy Mon Mar 19 15:56:19 2012

Roland --- Fungi do really enjoy carbs. That's why people often grow mushroom spawn on grain at first. So maybe Solomon is right and it's all about the glue. (Or at least partly about the glue.)

Brandy --- Good question! Are you sure that excess water is what was causing your problem? Our climate is very wet too and mulch doesn't cause a problem here. Water tends to drain down through the soil (unless you have a waterlogging problem) faster than it evaporates off the top (unless you live in a very sunny place like the southwest). (Lots of unlesses there, but you probably get the point.)

When I was working the kinks out of my mulching campaign, I did find that high carbon mulches will stunt plants since soil microorganisms grab nitrogen out of the soil to counteract the carbon. What are you making your kill mulches with? Wood chips and even tree leaves are too woody for the vegetable garden, even if they've been composting for quite a while. Paper and non-corrugated cardboard have also caused stunting for me. Mulches safe to put around vegetables include corrugated cardboard, straw, and grass clippings. If you put a bit of compost underneath, you can get away with using woodier mulches.

But here's another thought. Are you positive the mulch was even responsible at all? The most common cause of stunted tomatoes is cold. They're very sensitive to temperatures below 50 degrees, and if a tomato plant gets set back by cold weather, it could spend months looking puny.

To answer your specific question, though, I don't worry about mulching early (although I do pull back the mulch in the spring to preheat the soil if I'm going to plant a spring crop from seed.) When using vegetable garden type mulches, I mulch right up to the base of the plant because I hate trying to pick weeds through straw.

You'll have much better luck finding free cardboard if you live in a city. Refrigerator stores are supposed to be perfect for big boxes, and someone else recommended liquor stores. Even our local dollar store and grocery store will give us cardboard, but their boxes are smaller, which makes them less fun to kill mulch with.

Comment by anna Mon Mar 19 16:20:42 2012

Wow, great reply Anna! Thank you!

From what I researched about the stunting and root rot, and the wet state of the soil, I assumed it was compounded by the mulch. Although it was a raised bed, the yard I have is clay soil covered by only an inch of topsoil, so maybe seven inches of organic matter wasn't enough for the seedling? It wasn't temperature, I planted later with larger seedlings on purpose, I knew I wasn't experienced enough with tomatoes to risk cutting it closer to frost dates. However, I mulched with straw over newspaper, so perhaps your own experience with paper mulch may also be partly to blame? All I know is that I was sad to see the seedlings never grow an inch. Oh they put out tons of flowers and managed some tiny, tiny Roma tomatoes... They tried, bless their hearts, but never got larger than a foot tall.

Comment by Brandy Tue Mar 20 22:27:43 2012

In that case, I'd guess the newspaper might have been the problem. Lots of books recommend using it in kill mulches, and I will around woody plants, in a kill mulch I won't plant into for a few months, or with a lot of compost. But I feel like it's too high in carbon for an active vegetable garden.

Clay can be tough to deal with, though. It's possible that your issue could be water-related with the clay, in which case I recommend building upward as organic matter supplies allow.

Good luck!

Comment by anna Wed Mar 21 08:45:17 2012

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