Sunday, August 23, 2015

Breaking Down in the Garden -- Compost 101

If there was only one thing you could do to make your garden a better place what would it be? Why that’s easy, the addition of compost. This adding of decomposed plant material into the garden is the most surefire way I know to improve the soil and give your garden radiant, glowing health. The question, however, is how do you add compost to a garden that’s two plus acres large without robbing a small back. 

Easy. Play Lotto.

No, but seriously, if I tried to spread compost over all the beds in my garden each year, and top dress the lawns with a thin dusting of purchased compost, I’d be in the poorhouse in a moment. The trick is to make your own. It’s not hard to make compost, but it is time consuming, so I will confess right up front that I am a passive composter. This means I do not flip my compost pile, rather I just let it sit and do it’s thing, but it also means I get plenty of weed seeds that are still active in my pile, so in some ways, I’m making the garden more difficult to maintain. However, lets hold on a moment, because I’m getting ahead of myself here.

First what is compost? Compost is what you end up with when a pile of organic matter breaks down into humus after a period of time. The organic matter is broken down by the soil-borne fungi, bacteria and worms that are already in your garden, and it requires the right mix of green materials (nitrogen rich components -- grass clipping, weeds, vegetable scraps, etc.) and brown materials (carbon rich components -- dead leaves, straw, shredded newspaper, sawdust, etc.) plus the addition of water and oxygen to break down properly. If you have too much green material, you won’t get compost, you’ll get slimily, slippery, smelly ooze. Too much brown material, and the material will take so long to break down you’ll be able to be added to the compost pile yourself. So the balance is tricky. I use sawdust, because I don’t have enough leaves on my properly to balance out all the grass clippings and weeds and fallen apples I toss into the pile, and sometimes I have to buy straw. The brown material helps keep air in the compost pile, because you need aerobic bacteria (the ones that need oxygen to function) to work with the fungi to break down the material into heat, carbon, dioxide and ammonium. This ammonium (NH4) is the form of nitrogen plants need to grow and the only one they can actually take up from the ground. 

Compost is rich in nutrients and so can be used as a fertilizer, as an addition of vital humus or humic acids, and as a natural pesticide for soil, it can help a sandy soil hold moisture and help make a clay soli more porous. It’s like a wonder drug for your dirt.

So what are the rules to creating a compost pile?

1: You need a way to keep the pile in a pile. This is so that the heat created by the fungi and bacteria breaking down elements of the pile will not escape and the trapped heat will help speed up decomposition. This heat will also cook weed seeds and prevent the new soil you make from contaminating your garden beds with billions of tomato seedlings from last years cast offs. If you don’t build up heat, the pile will still break down, albeit significantly more slowly and with unwanted seeds still intact. Most people use compost bins, please note the plural, because you need to be able to turn the pile from one area into another, and you need to be able to start a new pile when the first start to really get cooking. You can buy a compost bin, they even have ones that you can spin around, but as I noted, I’m a bad composter so I have two big piles that I switch from year to year, one of which I’m using and the other of which is my active site. If I had the time and wherewithal, I’d build myself a three-box system with lovely slatted walls for ventilation. And, since I’m not flipping the pile on a regular basis, it would be great if I’d located it in a sunny location so that it had as much heat as possible. Unfortunately mine is in the shade half of the day, so although decomposition still happens, it’s much, much slower, especially when freezing temps arrive in the fall. 

2. Get the ingredient mix right. I’m going to give you a little science here, because it’ll help you understand the concept. We need a good carbon:nitrogen ration, plus some moisture to keep the good bacteria humming. Depending on whom you listen to, it seems that the most efficient composting ratio of carbon:nitrogen falls somewhere in the 10:1 to 20:1 range. Now this doesn’t mean 10 buckets of leaves to 1 bucket of grass clipping. Fresh grass clippings are super high in nitrogen, with a carbon:nitrogen ratio of about 15:1 . And dry, fallen, raked up leaves have a ratio of 50:1. What is lovely is that a bucket of lawn clippings plus a bucket of autumn leaves will give you the perfect ratio. So we don’t have to do the math to figure it all out. Unfortunately, I don’t normally get both at the same time, so this is why it’s nice to have the three-box system for creating a compost pile. In this, my perfect world, I would be able to rake up all my leaves (and those of my neighbors’) and put them in the first bin for use throughout the spring and summer when it’s grass-clipping season. (They’d have to be pretty big bins.) Then I’d throw a barrel or two of leaves down every week after the guys have mown the yard and dumped my grass clippings into the mix. My ratio would be perfect. But life doesn’t work like that, so I sometimes shred newspaper, but I mostly add sawdust (from my husband’s furniture making shop) or wood chips or straw that I buy by the bale when the nitrogen production of the garden is out of control. It’s also a smart idea to throw a few shovelfuls of garden dirt into your compost pile to get it going and bring the garden microorganisms in to start their work. Most people add kitchen scraps, but please avoid fish and meat and dairy as it attracts raccoons and rats and dogs. I am also blessed with chickens so their used bedding is added as well. Sawdust has a ratio of 325:1 so I need a lot less of it then I would need leaves, which is super helpful when the lawn is growing an inch a minute in season. Wood chips are 400:1 so I don’t really add them because they take super long to break down, but I will confess to using them as a way of starting new garden areas. I use them on top of cardboard to suffocate the existing grass, cover them with garden soil and compost and then wait until they start to break down to plant in them. It takes a long time, but I have lots of other garden projects to distract myself with. 

 3. Tend to your compost pile. This is where I fail. You should feed it consistently, which my lawn guys do, but I should be in there myself once a week with my carbon and often I forget. Turning every week would be the absolute best thing if you can, every other if you can’t. Mixing with a pitchfork (a chore I am bad at) every week or two to make sure that all of the materials are blended and interacting speeds things up super fast, as long as you’re pile is not too wet. It should be damp, not wet, wet equals slimy, too dry equals a slow pile. In a few months (if you are good) or in a year (if you’re bad like me) you’ll have delicious dark, crumbly soil that smells like fresh earth.

4. Make sure you have a mix of materials. The combination of different textures and nutrients created by the disintegration of many different kinds of organic matter will make your pile transform into a truly diverse mixture that’s the ultimate in plant nutrition. And don’t start too small, you need enough material to achieve critical mass, so it needs to be larger then a garbage pail, unless you have a small spinning composter that’s built for small amount. And don’t make it so large that you have no hope of turning the thing. That was my dilemma, but one I solved by just continually starting new piles down one side of my property. I now have an entire bank that ready for planting. The unfortunate thing is that if  I keep planting in my old compost piles, I’m going to run out of places to put it pretty soon.

Paige Patterson has too many pears to eat and is thinking about making jam and chutney today!

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