HUMBOLDT STREET, Brooklyn: Production of the cold frame began this week. For those of you I haven’t already bored to death with my epic tales of it’s future glory… Brad and I took off Monday & Tuesday from work this week to build a cold frame off our back door to extend the growing season. It will also act as a vestibule. Needless to say, it’s not finished yet. Plans for completion have been set for this afternoon, and I will post the full documentary of it’s progress once we are 100% done.
In the mean time I would like to dish out some dirt, that is to say, shed some light on composting. There are many ways to go, but in the city it’s hard! Options are limited. It’s not as easy to have 3 huge stalls devoted to the process of dirt making. This would be an ideal scenario. What I have going on in my urban situation is very simple. One galvanized garbage can with a few holes banged in the bottom (with hammer and nail) for drainage. See if you can spot it:
Ok, that wasn’t so hard, it’s right there!!
In my opinion the process of composting is intuitive. You can read a lot on what you are supposed to do and still not get it right. I’m definitely not an expert on soil composition and have very broad standards for mine. Mostly, if it looks good in color (dark) consistency (moist & crumbly) and smells “right” I consider it to be nutritious addition for my plants. This bucketful is well on it’s way:
My compost is mostly plant matter. The acceptable exceptions to this rule are shrimp tails, empty clams, muscles or other clean (meat free) crustacean shells. Many people will oppose this exception on the grounds of mercury and pesticide content or that it invites unwanted pests, like rats. But I believe these shells can be important additions providing chitin, which encourages growth of benifial soil micro-organisms and reduces the number of plant pathogenic nematodes. Egg shells also achieve this. The rodent issue is easily avoided with a well sealed bin like a trash can with a tight fitting lid.
I would not recommend meat or dairy in urban composting unless you are specifically set up for it. This means a very deep pit where the scraps can be buried undisturbed to break down with out stirring. This proves challenging in backyard buckets, and not worth the effort, stench, etc. If you want to get rid of this stuff organically, get a dog.
Layering and diversity of ingredients is important. Food scraps need to be cut into small pieces and balanced with garden material. Garden material is dry leaves, stems, branches and grass clippings etc. This proved problematic when I started my compost because my backyard is a concrete slab and nothing was growing. Luckily I had access to sawdust, which is a perfectly good substitute to start out. I also think it is ok to use shredded paper, although this is another material some would argue because of bleach and toxic dyes.
To start I stacked a layer of sticks and braches every which way to create aeration at the bottom of the barrel. Air is important because the bacteria and fungus need oxygen to live and work. If the mass is too dense or becomes too wet, the air supply is cut off and the beneficial organisms die. Decomposition will slow down and this is when you get a stinky cold mess.
Next I threw in a layer or garden matter, almost like a cushion or filter to reinforce the air pocket at the bottom. At this point in my gardening career this is all my clippings from deadheading and pruning, and ends up looking something like this:
I have a pile of this stuff to the side so it can dry out a little, and I can add as needed.
The next layer is the veggie scraps. We have come up with a pretty effective system in our household which eleminates any kind of stink or rotting issue. Instead of having a pail under the sink or on the kitchen counter out in the open, we collect everything in a bag in our freezer. The smaller the pieces, the faster you get dirt. Here is a typical food layer:
Coffee grounds are an excellent source of nitrogen! You can include the paper filter right with the grounds!
To cap it all off, I add a shovel or two of cheap bagged top soil on top of the food scraps. Then repeat layers until your bin is full – dry garden clippings, frozen food scraps, top soil – I always try to end with top soil. Basically what I am doing is creating layers of carbon (garden material) and nitrogen (food scraps) which will all decompose into dirt. The top soil speeds this up, sort of acting as a glue. Or maybe a teacher.
A couple more things… I do not usually add water to mine, even though it is a closed container, because my scraps are frozen the thawing produces enough juices for my local. Heat is the final component. A hot spot where the bucket can really cook will speed the decomposing process. The trash can should feel warm, even hot to the touch. When this happens you will know there is some good chemistry going on in there and soon you will have dirt! Depending on a million and one factors it should take about 6 weeks. Stirring and turning will help. I just use a shovel to mix it up a bit and bring the bottom to the top, probably every two weeks. The result is very rewarding.