Compost at Home

DEFINITION

I recently had a request asking about how to make compost at home. Most of us live in the city so I'll keep urban setups in mind. This blog will help you produce lots of great compost by enlisting the help of aerobic microorganisms.

Compost is simply a mass of bio materials that have broken down sufficiently so plants can access its nutrients. A compost pile is not just a pile of grass clippings, leaves and kitchen scraps that are randomly thrown onto a pile at the edge of a property. It is not a stinking pile of rotting scraps! If your compost pile stinks, you will find this short blog helpful.

What is an aerobic compost pile? An aerobic compost pile is an assortment of bio-materials properly mixed with lots of air and some water to create a world where microorganisms will thrive. The more active they are, the quicker you will have compost. When put together well, a good compost pile will always smell earthy and fresh, almost like loam. When you think of composting think creating a world that will put microorganisms into a healthy frenzy of activity and productivity. With a little diligence you can produce a compost pile ready for use in as little as 21 days.

MATERIALS

1. Use the Right Mix of Materials - You need green and brown materials. Greens are nitrogen sources like grass, green straw, lettuce, veggie scraps from making meals, green leaves and fresh manure. Browns are carbon sources like dried brown leaves, brown grass, brown straw, shredded paper and cardboard. I use about 1 part greens to 4 parts brown. Too many greens and your pile will grow too hot and cook the microorganisms. Depending on where you live, it may take a few batches to find what ratio of greens and browns work best for you. The temperature you are looking to achieve in your pile is around 135 - 158F (57-70C). Once you hit 160F (71C) you will fry all living things in your pile and lose the benefit that they bring to your garden. You can buy composting thermometers for around $24. If you don't have access or a budget for one, just use the hand method. Plunge a hand 1/2 way into the pile. If the heat allows you to keep your hand in there without burning, you are good. However if the heat is too much to keep your hand there, the pile is too hot. You can also use a length of 1/4 inch (6 mm) rebar. Press it into the middle of the pile and wait for 5-10 minutes. Then remove and grab the end with a hand. Again, if you can hold on to the bar without letting go, you should be good. The right temperature will be quite hot, enough to make you think of letting go. Remember that if you are building a hot compost pile, you will need to pull it apart and reassemble it every 3 days for a week or two.

OXYGEN

2. Provide Lots of Air - Aerobic creatures breathe air so if you pack your pile tightly they will use up the air very quickly and die, making way for anaerobic creatures to take over (that's when things get smelly). So just pile up the materials naturally without compressing. Don't place a heavy piece of board or heavy cover on the pile. Keep it light. The compost in my hand below was ready after only 6 weeks.

MOISTURE

3. Provide Sufficient Moisture - Like us, our aerobic friends need water to thrive. As you build your 1 to 4 green to brown ratio of materials, spray each layer as you go with water. They thrive best in an environment where moisture is at about 65% throughout the pile. So how do we achieve that? Again, use the hand method. Grab a big handful of the pile and squeeze really hard. If it is at 65% you should be able to get 2-3 drops of water out of that handful. That is about 65% moisture. Easy.

VOLUME

4. Build enough Volume of Materials - We'll talk about how to handle small amounts of composting materials in a bit. But just know that a cubic yard or metre of materials is ideal. I make at least 2 cubic meters of compost yearly which is just enough to cover our front yard food forest with 2 inches (5 cm) of compost. Because we have 4 chickens, they provide a few wheel barrows full of manure-inoculated straw which we also add to the compost before spreading it on our garden in the Fall. Just remember that if you are growing food intensively you need to add nutrients regularly to avoid nutrient depletion. If you don't add something like a good quality compost and manure then you will be forced to add fertilizer which isn't really that healthy for the soil.

It is easy to make a 1 cubic yard or meter container using wooden pallets. Use one as a floor. Attach the other four pallets with light rope around it. It has lots of aeration and keeps the pile from getting blown around. You can also use a heavier gauge wire fencing material. Shape it into a cylinder. Finally, cover the top with light impermeable material to keep rain off the pile. You don't want it to get soaked. Just 65% moisture. Notice this composting unit is right close to the back door NOT at the far end of the yard. Why? Because when put together properly you won't smell anything awful. Also, a hot composting pile will keep away little creatures, flies and insects. A unit close to you will be visited much more easily than a unit far away. If you don't like the looks, decorate it. Go ahead, make it look fabulous (paint, drawings, hangings).

ADDITIVES

5. Include Optional Additives - Along with the usual materials, you can add others to enhance the biodiversity and quality of your compost pile. Add things like dried and finely ground egg shells, coffee grounds, ripped apart tea bags, molasses (without sulphur) dissolved in warm water, buy fish hydrolysate or make your own fish concoction by putting some leftover fish guts, skin and bones in a blender with water and blend until it becomes a slurry fluid with most clumps gone. Add rock dust and bio-char (Google it). I sprinkle or pour additives per layer as I build the compost pile.

An added word about bio-char. It is sequestered carbon (charcoal bits) with a micro structure that is different that regular charcoal or ash and provides housing for beneficial micro-organisms. Once in the soil it can benefit for 100 years or more. But it needs to be inoculated with the microorganisms before adding to soil. You can do that by adding it to your compost mix. Check your local stores to see if they carry any or make your own -- which is much less expensive.

ACTIVATE

6. Activate the Pile - Once you have the proper pile put together, activate it. If you are not a walking pharmacy, use a gallon or two of human urine mix. It is clean, filled with NPK (Nitrogen, Phosphorus, & Potassium). I use a gallon milk jug to collect it and dilute it 1 part urine to 9 parts water. Pour it on the top of the pile in different places. You can also use it full strength or use 1 part urine and 1 part water. Again, you will not notice the smell because all the brown materials in the pile are carbon. Carbon eliminates odors. Micro-organisms like sugar, so a molasses water solution will help (1-2 Tablespoons/gallon of water). You can also buy compost activators in powder form if you feel obligated to give away more money.

COMPLETION

7. Identify When a Pile is Done

In as little as 4 weeks of observing and turning the pile, it will no longer heat up and be ready to apply. But check out how it looks, smells and feels as well. You may want to let it age a bit to achieve a more loam-like appearance and smell. Don't worry about how long or short it takes to break down the materials. The important thing is to watch the heating and cooling cycles and note the appearance change from separate materials of greens and browns and textures into a basically combined mass of dark brown fibrous loamy consistency. Also, there is no rush to apply it immediately. I leave mine until after the Fall harvest to spread it evenly over all garden areas. Check in the next section for various ways to apply compost.

OPTIONS & APPLICATIONS

8. Use Other Methods of Making and Adding Compost Materials - If you are in an urban setting with little space, you can compost on the go. We acquired two 3 gallon (12 liter) buckets with lids from Dairy Queen. The buckets are used to hold strawberries to add on top of sundaes etc.. We placed the buckets on our kitchen floor. One bucket is full of crushed old brown leaves. The other we use to build our compost mix. Add about 3 inches (7.6 cm) of brown leaves. Then add kitchen food cuttings/items in 1 inch (2.5 cm) length cut pieces on top of the leaves and give a good mix. Place lid riddled with 1/2 inch (12.7 mm) drill holes to cover and aerate the compost mix. Repeat this daily until the mix fills the bucket. Add water to achieve a 65% moisture level. The mix is now ready to add directly to the garden. During the winter just place the mix on top of any snow that covers your grow areas. The compost will be ready on top of the garden when Spring arrives. Collect a few garbage bags full of leaves in the Fall, enough to make compost buckets until the next Spring.

If you don't have access to many leaves, use shredded paper (crisscross pattern only short pieces), shredded cardboard or shredded newspaper (not glossy coloured). Sawdust or shavings from a local lumber yard or hardware store that cuts lumber will do. Dust/shavings from lumber yards is better since the wood will not have been poison-treated yet. Anyway, build a 4 parts brown to 1 part green mix. The great thing about this method is that the browns are carbons and eliminate door. So you will only have to empty the compost bucket every week or two depending on how many people are eating at your place. Our winters go down to -40 F (-40 C) and even colder. It is a relief that we have a week or two to wait for warmer weather before having to take out the compost.

Another way of adding your mix to the garden is to bury it about 4-6 inches (10-15 cm) deep and about 1 ft (30 cm) away from the plants. In this way, the compost, as it heats up, will not burn the plants. In a few weeks the plants be able to benefit by the new compost.

Finally, you can add the compost mix on top of the garden and just let it break down from there. This way you do not need to keep it so far away from the plants. Still keep it about 3 inches (7.6 cm) away from the plants.

There is so much to learn about composting. But this should produce for you a great quality compost. Have fun getting into the world of making all the food (compost) your gardens need at home, cost effectively and in a way that is better for your soil and safe for kids and pets.