(This topic came up in the introduction forum, and it was suggested that I post it here. Enjoy!)
A selection from my blog:
Fall is one of the easiest seasons during which to start a compost pile because of the abundance of organic material likes fallen leaves and spent plant stalks. One of the plants you'll hear about often in connection with compost is comfrey (Symphytum spp.). There's been much ado in the blogosphere and gardening/homesteading community in general about the benefits of comfrey to the garden, both as a fertilizer and as a compost activator. Unfortunately, I haven't gotten around to adding comfrey to my herb garden. There is, however, a wonderful herb that can be used in the same manner as comfrey and that I have in abundance: Yarrow (Achillea millefolium). At this time of year, her (and by "her" I mean yarrow's) beautiful heads are heavy with seed, and her time to aid in the stocking of my medicine cabinet is pretty much over. She's an herb for all seasons, though, and autumn finds her the unfailing companion of Madame Trash Heap (as The Husband affectionately refers to our compost pile).
Just like good ole comfrey, yarrow acts a wonderful compost activator to speed up the decomposition of the green and brown materials you've added to your pile. It's been said that a single yarrow leaf, finely chopped, will give you marked results in as much as a wheelbarrow full of compost materials. This activation ability is connected to yarrow's ability to concentrate both sulphur and potassium, along with other micronutrients such as copper and phosphates. This year, knowing that I'd have an abundance of stubborn sod and crabgrass to break down in my pile, I added a couple chopped leaves of yarrow along with a handful of soil between my green and brown layers. In the biodynamic community, it is recommended that the yarrow be enclosed in the bladder of a male deer because of the herb's relationship in treating that organ (in a nutshell), hung in the sun throughout the summer and buried shallowly in the soil throughout the winter, before being added to the compost in the spring.