Agriculture Reference
In-Depth Information
Activators
Activators are extra substances that stimulate the composting process. They can be syn-
thetic substances, which I don't recommend using, or they can be natural such as blood
meal or bone meal. I don't use these either because of mad cow disease concerns, but I do
use a few things.
Activators aren't crucial, so if you want to keep the external inputs to a minimum, you
don't need them. People who are really into making the best compost may enjoy using
some of them, but there is something to be said for keeping compost simple and using ma-
terials from your site as much as possible. Some of the potential benefits of using activators
are a faster time for the pile to finish, a better finished product and less odor. Some activat-
ors such as clay, humates, calcitic lime and gypsum also decrease nutrient loss from the
pile, especially nitrogen, which is a big deal.
When I'm building a new pile, I inoculate it with finished compost, generally as much as
10% of the pile or even just a few shovels if that's all I have. I'll also add as much as five
pounds of humates per yard of raw materials, although that can get expensive. You'll read
more about humates in the biostimulants chapter. It seems counterintuitive to add them
when the ultimate goal of compost is moving it towards becoming humus, but adding
humates can drastically improve the composting process.
I use as much as 10% clay in the pile. You don't want to add clay directly to sandy soil,
but composting it gives it a chance to form a clay-humus complex. Even if I have clay soil,
I'll add some to the pile to get this complex happening, because it helps the organic matter
stay in the soil. Bags of bentonite clay are great, or even just a clay loam soil works well.
This can get expensive, too, but even a small amount of clay is very useful.
I'll cover Effective Microorganisms (EM) and biostimulants later in the topic, but I will
mention here that inoculating the compost with EM will speed up the process and may con-
tribute to a decomposition that is more controlled and less oxidative so that nutrients are
better retained. Odors are also greatly reduced. EM can be mixed with an equal amount of
molasses and 100 parts water and sprayed onto compost until the desired moisture is ob-
tained. That's 2 teaspoons each of EM and molasses per quart of water. I do this whenever
I'm spraying the rest of my garden, which might be monthly.
Rock dust, covered in detail in the chapter on supplementing nutrients, is an incredible
addition to the compost. Just sprinkle it in as you build the compost or work it in from the
top. The nutrients have an opportunity to bind with the organic matter and are thus more ef-
fective when they're eventually incorporated into the soil. The dust will also improve the
composting process. Different experts say to apply anywhere from 2 to 50 pounds of dust
per cubic yard of compost. I use 20 pounds and I use a non-quartz dust such as basalt rather
