What’s Brewing is a podcast all about compost tea hosted by Troy Hinke.
Troy Hinke served as Rodale’s Compost Research Specialist alongside the founder of Soil Foodweb Inc., Dr. Elaine Ingham. Troy now runs Living Roots Compost Tea, where he offers several services including consultations, compost sprays, and compost brewing, among others.
Episode three of a 10-episode series on compost teas, host Troy Hinke talks about compost, types of composting, and how to get the most biology out of that compost to brew as quality compost tea.
What is Compost and What is it Made Of? (01:29)
The definition of the verb form of compost is the oxidative breakdown of a variety of organic matter. There are many ways of producing compost, but this episode will focus on three types of composting: vermicompost, thermophilic composting, and static composting.
Any and all types of compost will be composed of a variety of feedstock or ingredients, which is basically a variety of organic matter, water, and air. Different microorganisms will be active in different environmental conditions. Therefore, using a wide variety of organic matter will help cover many, if not all, of those bases because a wide variety of organic matter will yield a wide variety of microorganisms.
It is also preferable to use a variety of sizes when choosing which organic matter to use. If all the organic matter were in large chunks, there wouldn’t be enough contact between surfaces, and the heating action in the compost pile would not be achieved. On the other end, if all the organic matter were small and powdery, there wouldn’t be enough airflow in the compost pile. The best material would be a mix of both large and small materials.
Green Material vs. Brown Material (04:03)
Green material are organic material that have a low carbon to nitrogen ratio, from 30-100 to 1 carbon to nitrogen ratio. When we refer to green material, we’re talking about plant matter that was cut green so that all of the sugars, carbohydrates, and proteins remain in the plant. This material breaks down easily.
On the other hand, if that green material weren’t cut and was allowed to die and turn brown, then that would be considered as brown material. Brown material have high carbon to nitrogen ratio, are high in lignin and cellulose, and therefore take longer to break down.
Green material serves as food for bacteria, while brown material serves as food for fungi.
A High Nitrogen Source (06:19)
Some compost piles, usually thermophilic piles, will also need a high-nitrogen source to kickstart the microbial action and get the compost pile to heat up faster. When using a high-nitrogen source, it is best to keep the material to no more than 10-20% of the total volume of the compost pile.
High-nitrogen sources are plant-available alfalfa and manures.
Keep in mind: when using manures, it is important to avoid anything that uses antibiotics because it kills the exact microorganisms we’re trying to grow. It is also important to avoid manure from animals kept in feedlots because those animals are usually fed high-salt diets, and high salt content keep bacteria at bay.
Oxygen and Temperatures (08:14)
Oxygen is needed in a compost pile, and how much the pile can be aerated depends on the shape of the pile. Oxygen can be delivered either by hand turning the compost pile or possibly using forced air like a blower system in an aerated static pile.
If you’re having trouble with getting and keeping your compost pile’s temperature up, you can try stacking a larger pile to hopefully get the temperature up. While if the pile’s temperature is too high, and you need to keep it cooler, you can manage the pile in windrows instead to have more surface area exposed to the air.
The management of the air and management of the pile are what affect the temperature of the compost.
Water is one of the ingredients needed in a compost pile, and with most compost piles, the optimum moisture is best kept at around 50%, which is the consistency of a wrung-out sponge. Because worms breathe through their skin, vermicompost piles are best kept at 80% moisture. Otherwise, the worms will dry out and die.
Hand squeeze moisture test. This test is a simple test that checks a rough estimate of your compost’s moisture content. To do the test, grab a small handful of compost with your fist and squeeze the material.
50%. One to a few drops came out from the handful.
40%. The material sticks together, but no moisture came out.
30%. The material falls apart in your hand.
20%. The material falls apart and can be blown off your hand.
Compost Ingredient Ratios (11:36)
Most people would go for a 50-50% ratio of green and brown material, but that can be tweaked depending on what you’re trying to achieve with the compost pile.
A basic recipe for trying to get more fungi going in a compost pile would be to have 60 to 70% brown material with 40 or 30% green material. If using a high-nitrogen source, subtract 5% off each of those if you were going to do 10% of a high nitrogen source, so you do 65-25-10.
If you’re trying to get more bacteria in a pile, then you’d want to go with a ratio of 50 to 60% green material in a pile. Note that you can really overdo it by putting too much green material into a pile, and it ends up getting soggy or sloppy and sometimes nasty, so it’s best to stick to a recipe of 50-50 or 60% greens and 40% browns if you’re trying to get more bacteria or even ratio.
Tips for Any Compost Pile (13:56)
One way to incorporate more saprophytic fungi into your compost piles is to add forest soil from a nearby forested area. Look for leaves or sticks and check the underside for white strands of mycelium. If they’re present, there’s going to be microscopic mycelium underneath the soil.
Grab a handful here and a handful there, taking care not to rob the soil in that forest area, but just enough to get native microorganisms that will survive in your environment.
Starting Worm Composting at Home (17:40)
Optimum temperatures for worm composting are 60-80°F (15.5-26.6°C). Other than African nightcrawlers, the most popular and pretty much the only worm that’s used are Eisinia fetida, manure worms, tiger worms, but most popularly known as reg wigglers.
Order worms from a breeder close by, close enough that shipping won’t take too long so that the worms are more likely to survive and be healthy when they arrive to you. Order one pound of worms per square foot of surface area.
Worms will also need bedding, which can be anything from old compost, peat moss, coco coir, or shredded newspaper. If you’re using anything but compost, soak the material in water to ensure moisture at the optimum level of 70-80%.
When it comes to food for worms, add both green and brown material. When using worms to compost food scraps, be sure to add carbonaceous material such as ripped paper. When doing straight manure, be sure to add brown material such as straw or wood shavings. Using compost to feed worms will create even higher biology compost.
“One other good thing about worm composting is that worms can work through material even faster than just the regular composting process.”Troy Hinke
Purchasing vs. Making Vermicompost (24:34)
Get vermicompost as close to harvesting as possible, not something that’s been sitting in a plastic bag in a big box store for several months. It’s good to get vermicompost from someone who can ship it to you directly, having just been harvested within the past few days to a month here. That compost will be a lot fresher with more active biology.
Thermophilic Composting or Hot Composting (25:35)
When thermophilic composting, focusing on the biology specifically, it’s best to maintain temperatures above 131 degrees Fahrenheit (55°C) but below 160 to 165 degrees Fahrenheit (70°C) and keep the moisture levels at 50% to keep the microorganisms happy.
With thermophilic composting, we need to maintain a thermal mass of at least three to four feet in order to retain the heat in the pile. If you get much smaller than this, you can get a pile to heat up, but you’re most likely not going to actually retain that heat for as long as needed to kill pathogens and weed seeds.
It’s important to turn the compost pile when the temperatures reach 160°F (70°C), when the temperature suddenly drops 5-10 degrees, and when there’s suddenly a nasty smell coming from the pile, usually the smell of ammonia. This means that the pile is not only turning anaerobic, but the nitrogen is also being lost in gaseous form.
Lastly, turn the compost pile when you see actinomycetes or actinobacteria, organisms that look like a white powdery substance, normally found six to nine inches deep into a pile. Actinobacteria in a compost pile is normally a sign that there’s low oxygen and has been shown to suppress mycorrhizal fungi in soils.
Thermophilic compost is finished when the temperature drops down to or close to ambient temperature.
Static Composting aka Slow, Cold Composting (39:03)
A great way to get high-biology compost, static composting is most commonly done by hobby gardeners at home to turn garden waste into compost and soil. This is done by putting garden waste like mowed grass, fallen leaves, vegetable stalks into a pile and allowing it to decompose for about a year or so.
With Any Kind of Composting (42:07)
In any type of composting, it’s important to keep as much brown material as green material, or even more brown material than green. On any scale, keeping this green material covered with brown material will keep odors and pests down.
The most common mistake people do when trying to compost their home scraps is putting far too much green material and not enough brown material, which turns the pile soupy and sloppy. The remedy is simple: add more brown material equal to or more than the green material.
Vermiculture Technology Earthworms, Organic Wastes, and Environmental Management by Clive A. Edwards, Norman Q. Arancon, Rhonda L. Sherman