Over the past year we have enjoyed trying to meet the challenge of compost independence. Our goal is to produce all of our own compost on site, and we came quite close to that this past year. Our main use for compost is as a soil amendment for our growing beds. We apply a layer to each bed at least once a year, especially before planting heavy feeder crops. In addition, depending on the crop and what has been in the bed previously, we may also sprinkle on an organic fertilizer such as fishmeal or granulated poultry manure. Then the amendments get mixed into the top few inches of soil and the bed gets smoothed out into a nice flat surface ready for seeding.
Our compost set up is very simple and was cheap to put together. It is just a series of pallets secured at the corners with wood or metal brackets. We use pallets as the doors too and tie them on using old pieces of bale twine. By having a series of compost compartments, it is very easy to turn over a pile into the next compartment, so we have piles in different stages of decomposition. The pile at the end all the way to the right is the freshest pile where we add our kitchen scraps, garden wastes, and other compostable materials. We only add fresh materials to the old piles if we really need to when turning. The first turn is an opportunity to assess the state of the compost. Ours can tend toward being too nitrogen-rich, so we have needed to add some additional sawdust, leaves, hay, or ash at this point to make it more balanced.
How frequently we turn the piles depends on how much compost we are using and how much material we are generating that needs to be composted. I would guess each pile gets turned every 3-5 weeks.
This system is working very well for our older garden which is between 3,000 and 4,000 sqft. In the 2018 season, we plan to experiment with some new techniques utilizing our BCS tractor more for mixing in order to supply our larger field garden (about 7,200 sqft) with compost.
Here are some of the biggest lessons learned from this past season of composting:
More Surface Area = Better Compost.
Our best innovation with the compost this past year was using our flail mower attachment on our BCS tractor to shred crop debris before adding it into the compost. This works very well for cropped out plants such as peas, green beans, cabbages, cauliflower, broccoli, kale, swiss chard, for trimmings such as leaves from carrots, radishes, beets, etc, and for garden weeds preferably pulled before going to seed. We dump the debris in a line on the ground and run the flail mower back and forth over it. It is amazing how it reduces the material to a fraction of its previous size! All of these things could be composted without being shredded, but the shredding does a lot of the work right off the bat and gets the compost going much faster and hotter. It’s like chewing your food before swallowing it – a very important step in digestion! Whatever you do… don’t add whole tomato vines to the compost. I promise you will really regret it when you go to turn the pile!
We also use the chipper attachment on our BCS tractor to chip up more woody plants such as pepper plants and brush.
It’s also helpful to use fine material for your carbon elements. We started picking up sawdust this year, which has worked wonders on the structure of our compost. We use some hay, but know it would work better if it was shredded up more (We have some ideas to work on that for next year). To prevent clumping, we add the hay in thin layers between additions of other materials. We also use some woodchips in the compost, but preferably the finely shredded ones that we make ourselves, not the chips we have dropped off from local tree companies which are too chunky and take too long to break down to be a primary carbon source for the pile. Leaves are probably the single best ingredient for making compost. But, if added without being shredded, they can form solid mats in the pile that do not decompose well. It is much better to shred them before adding. We use a vacuum shredder to collect and shred leaves in the fall. We have yet to try the chipper on the leaves, but we did find that if piled up, we can use the flail mower to shred them. This fall we got a big load of bagged leaves from the town, which we have stored under cover to keep dry so we can use them throughout the year.
Go Heavy on the Carbon
One of the problems we kept running into was not adding enough carbon into our compost. Previously we were adding more chicken manure into our compost, and that along with big loads of crop debris and weeds was too much rich nitrogen. When we would go to turn the pile, it would be too heavy, wet, and sticky. It didn’t have enough aeration and none of that fluffy structure. The problem was that we didn’t have that great of a carbon source on the farm (yet). We do have lots of hay, but as I mentioned, needs to be more finely shredded if used as the primary carbon source. We don’t have a ton of trees on the property, so leaves could not be our primary carbon source either (though we did just get a big load dropped off from the town of Thurmont!). We ended up giving sawdust a try this past year and we really liked it. It is a very finely shredded material, it’s cheap, light, and adds a good structure and fungal element to the compost. Once we got that good carbon source established, we stopped shying away from adding a lot of it, and it has made a huge difference in the quality of our compost. When in doubt, always go heavy on the carbon! It should make up at least 50% of the pile’s volume. One other change we made is that we stopped adding chicken manure to the pile, which really helped balance out our carbon-nitrogen ratio and reduced that sticky-wet structure.
Keep it Covered
Our piles also used to get rained on too much. This compounded with the nitrogen issue to make the structure too wet and not aerated enough. Now we use scrap pieces of metal roofing and tarps to keep our piles mostly covered. They still get a bit of rain, but not too much, and now the structure is so much lighter and more aerated. Much more life can flourish in the aerobic environment.
More Material at One Time
We have found it helpful to load up our pile as much at once as possible. We often do big days of cleaning out crop debris, weeding, and shredding so that our first container can get as full as possible. This makes it heat up faster and gets the composting process going. In between those days, we’ll still add kitchen scraps and trimmings to the pile (followed by a bucket or two of sawdust or leaves), but these additions are very small compared to the bulk materials.
Keep Disease Out
Don’t get so caught up in wanting to use every bit of garden biomass in your compost that you sacrifice future plant health. Do your best to keep diseased plants out of the compost, because those diseases may survive and infect next year’s crop. This year we kept all of our tomato plants and most of our squash plants out of the compost because we had a lot of disease in those crops.