By Joshua Burman Thayer
It only takes a few cool evenings and wet mornings to give a sense that fall is coming. Squirrels stash nuts and songbirds fatten on dry seeds, giving us a little help with clearing away the summer plant residues as we make room for cool season crops. Now, as you are clearing out your summer beds, it’s a great time to revamp your compost pile as well.
One motto I use for composting is “Lasagna for life!” Like a good lasagna, compost should be built in many thin layers. Layering is how nature builds soil year after year in a slow, natural cycle. Be patient and be moderate in how much you add to each layer to replicate nature’s pattern.
Build Your Stalls
There are plenty of single-chamber compost bins on the market, but I prefer a two- or three-stall design. With two stalls, you can have one stall where you add new material (food scraps and garden clippings), and the other where you are “cooking up” new compost to use for dressing your beds. With three stalls, the third holds your finished compost. You can buy pre-made stalls, or you might construct them from scrap wood or old pallets. An advantage to a two- or three-stall method is that the compost does not need turning. It will take 6–12 months for a pile to be at full capacity, and then another 6–12 months to age.
Seven Layers to Success
Layer 1: As you start a new pile, prepare a foundation for your compost by placing a six-inch layer of small branches as the base of the pile. This allows aeration of the pile, which helps it heat up.
Layer 2: Cover the sticks with a layer of garden soil, which helps inoculate the pile with good local microbes.
Layer 3: For the next two weeks, pile on the kitchen scraps, which is the main fuel for your pile. The most common mistake I see homeowners make is overloading this layer. Food scraps are nutrient rich, but they can get slimy, which is why you want the next layer.
Layer 4: This is the carbon layer. Over the kitchen scraps, add a 2-inch cap of shredded paper and dry leaves and grass. If your food scraps are slimy, increase this layer.
Layer 5: Now add a fine, ¼-inch layer of wood ash. Do not overdo this layer. In the right proportion, wood ash is a valuable source of potash, and it also dissuades pathogens in the soil.
Layer 6: Now add 1 to 6 inches of garden plant residues. Note: Remove any very woody stalks as well as any diseased plant residues.
Layer 7: Now add a 1-inch soil cap of garden soil.
Now you want to repeat the cycle again and again.
Note: when harvesting finished compost, filter it through a ½-inch mesh screen to remove larger particles. These can then be used in the garden soil layer of the next pile.
Want to boost your pile? Wet it once or twice a month to get a spongy consistency and be careful not to keep it too wet.
Things to avoid in your pile: bones, oils, meats, woody material.
This Gardeners Notebook is one of Joshua Burman Thayer’s monthly newsletter columns. He also contributes longer articles for Edible East Bay’s print magazine, all archived at edibleeastbay.com. Look for Joshua’s food forest article in the Spring 2018 issue of Edible East Bay, and check out his design site: www.nativesungardens.com