Permie_Emmy_Sheet_Mulch
Raking it in

Anyone who works on their garden knows that compost is the thing you put on plants to make them do well. Few people know why unless they’ve dabbled in a little soil science.

While this blog doesn’t aim to repeat the knowledge imparted by most other permaculture blogs, it does seek to divulge some of my personal experiences in permaculture techniques, to help prevent you from making the same mistakes as me. So we’ll cover a quick background here and then go on to my most recent foolishness.

Why is Compost so Damn Good?

I’m not going to give you a science lesson but simply, when we employ permaculture techniques, the idea is to accelerate the success of plant growth. In our dying world, it is no longer enough to sustain ourselves; we need to go further to regenerate the mess we’ve made and to do it with a little urgency. Succession in agroforestry terms basically refers to the stages in which ecosystems move through, from the first pioneer plants (or weeds as you laymen like to refer to them), up to a mature forest.

The soil is also making a personal journey in that time, most basically moving from bacteria to fungi. Bacteria breaks down green stuff like leaf drop, feeding on the nitrogen in the plants. Fungus breaks down brown stuff like straw and dried leaves, feeding on the carbon. In order to accelerate succession, we need both. Compost is a lovely amalgamation of both of these things with bacteria and fungi bumbling along in there, breaking down the stuff we put in, building soil for the plants we want to grow. A rough calculation for this is that you need 40% green stuff, 40% brown stuff and 20% high nitrogen (manure or kitchen scraps, but manure is better). I’ll address how to make quick hot compost another time, but for now, this is about my adventure with sheet mulching.

What in the Heavens is Sheet Mulching?

When we make compost, we tend to make it in a nice, neat pile, relatively close to the garden. However, this still requires that we distribute it around the garden with our back-breaking labour. Sheet mulching is a beautiful technique which increases efficiency by building compost on the spot, pertaining to the permaculture principle of relative location. Not only does this make our lives easier, it also keeps the ecosystems that develop in the soil undisturbed. While turning compost and moving it to put it in place allows oxygen to enter, which helps to fire up the decomposition process, it also disturbs the complex life systems forming inside. Imagine you’re a happy little basteria, building a life for yourself down then, having built your own community and home with other bacteria. You’ve got yourself a bacteria job and you’re putting bacteria food on your bacteria table for your bacteria kids, taking them to their bacteria extra-curricular activities and having a bacteria pint down the bacteria pub with your bacteria mates. Then all over a sudden the dreaded natural disaster of the ‘spade’ wipes out your whole bacteria life and family, and you have to start over again from scratch, or worse, you get burned up in the process. Sheet mulching keeps those systems intact and undisturbed, and keeps them happily working away.

It’s basically making compost in the bed, which improves the soil straight off the bat. Recently I was reading a blog by a highly Christian, middle of America, homesteading Mummy who referred to this technique as ‘lasagne beds’. This made me chuckle but I really liked it as a descriptive title.

Collecting_Brown_Carbon_Sheet_Mulch
Collecting Brown, Carbon Material

So it’s this simple…or so I thought. You dig you bed. Then you place a layer of high nitrogen (manure most often), followed by a layer of green material (weeds, leaves, etc), followed by a layer of brown material (dry leaves, straw, rice husks). This brown material should be wet. You need generously thick layers of each and over time you pile these up over and over, which decomposes making rich composty soil in place. Not only this, the covering of the soil suppresses weeds, preventing erosion by rain, and holds water in the soil.

So Where Did I Go Wrong?

The tropics are luscious, thick eco-systems of pure production, but the nutrients are held in the plants, and not so much in the soil. The moment it gets in the soil, these overarching trees are sucking it up and expanding their growth. Not only does this mean you have to constantly feed the soil, it means that as quickly as you work to manage the growth, the jungle extends its spidery tendrils to take the land back.

When I laid down my sheet mulching, I thought it would be most effective to hoe the land first and clear the weeds out, to prevent them growing through. You can, in fact, just leave them and pile on top and the deprivation of sunlight from the other layers will kill them off, allowing their nitrogen to leech back into the soil. That was my first mistake; doing too much work for no reason. Just too in love with my hoe.

Mulching_hoe_permieemmy
Mulching with my hoe

My second mistake was thinking those weeds would die once I pulled them up, because logically that’s how life works no? No. These weeds are resilient little beggars.

I used dried leaves as my brown layer as we had an abundance around the site, but I found that the weeds underneath that I had pulled up, continued to grow searching branches, weedling through the leaf layers to find the sunlight, while their roots struggled to find solid ground. Often I feel like I’m personally doing this in my daily life, so I could most definitely sympathise. While the majority of stuff was decomposing under the top leaf layer, there were a selection of more viney weeds that would just not give up!

After speaking with one of my permaculture mentors, Itai Goldman, (when I say speaking, I mean freaking out and having a mild nervous breakdown) what I realised I should have done was the old bio-cardboard trick. Luckily, I’d been fermenting up a good old witch’s brew of nitrogen weed fertiliser in the background so I had that at my disposal to use. Rather than digging up all the weeds, I should have soaked the cardboard (make sure it has no ink on it) in the ferment and laid this over the weeds. That way this opaque layer would really stop them getting sunlight. Then I build my lasagne layers on top.

I did this in the end over the layers I had already put down and just piled more over the top and it worked. It stopped those weedy greens struggling to come back through. I was also a little more picky on what I laid as green material. I used cut-grass as the lack of roots meant that the grass would die off quickly without struggling to regrow.

Sheet_Mulched_Raised_Sunken_Beds
Sheet Mulched Raised and Sunken Beds

The beds are happily mulching away now. I haven’t planted in them yet although you can plant pretty much straight away. As I used raised beds, when it rains the water collects in them and the mulch holds them. If it’s dry, at the beginning, I would water the beds a little to encourage the brown leaves to decompose, as when they dry out they do nothing but sit and sometimes blow away in the wind.

What I Learned?

You can read all the books in the world about this stuff. You can indulge in all the blogs with different techniques. Only when you start to do it, do you realise that everything really is site-specific. I didn’t realise the voracity that these vine weeds would seek to stay alive and no blog or permie book really talks about that; because it doesn’t occur on their sites.

Next time, I’ll stand back and observe for longer and really take into account what is occurring on my site and what is likely to be a setback for the generic technique I’m applying, or should we say a hurdle I may need to overcome. Just because our PDCs taught us a little knack we can use for growing, doesn’t mean we shouldn’t be consistently thinking about how our site specifically will work with this technique, and what feedback loops the system might throw at us. As our good buddy Elvis taught us ‘Wise men say, only fools rush in’.

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