Thursday, March 9, 2017

Compost Bins

"V" wrote in asking about my compost bins. Actually, he was asking where I bought them. Here on this farm, I tend to make my own when I can, rather than buy it. Here's what I've done......

Above......I decided to build the compost boxes in a heavily shaded spot under a large tree. No crops could be grown there. Plus the spot was adjacent to my driveway, making it easy access to bring organic material to the boxes. So I found 11 sturdy pallets in good condition. 

Above, another view. 

I connected the pallets together using scrap lumber and nails. Since these are permanent boxes, I opted not to tie the pallets together. I wanted them to be more solid than my grow boxes. 

Above, a scrap of plywood nicely secured the outside bottom of the boxes. And where possible, I directly nailed pallets together. 

Above, I drove stakes into the ground and nailed the pallets to them. This firmly is holding the pallets in place. I would prefer to use metal stakes of some sort, but I don't have any at this time. Eventually I'll come across some, and will replace the wooden stakes with metal ones. 

Some of the pallets had closely spaced slats while some had wide gaps. I nailed plywood scraps to the pallets to fill in any gaps. 

With the pallets all secured and wide gaps covered, I started getting the boxes ready for receiving organic debris. I put a 2 inch layer of cardboard in the bottom. I have found that it's easier this way because it helps me determine where the bottom is when I empty out the finished compost. Usually some of the cardboard is still intact and visible. Oooooops. Forgot to line this box with plastic. 

I have a number of recycled black trash bags on hand. I'm using them to line these boxes. Anything that seals the sides could be used....old tarps, poly film, feed bags, etc. The idea is to help retain moisture. In my climate, if I don't line the boxes, they dry out too quickly. 

The black plastic is secured using a nailed on milk jug cap. I've had good success using this method. 

With the box now constructed, it's time to make the fourth wall -- the removable door. I've chosen a lightweight pallet. But it has wide gaps between the slats. 

So I covered them with a double layer of heavy duty cardboard. Just nailed it on using roofing nails. I could have used plywood, but since the door is removable, cardboard can be easily replaced each time I empty the bin. 

On top of the cardboard I applied a black trash bag. In this photo, I haven't nailed it on yet. But I'll use the milk jog caps to secure it in place. 

Almost complete. I need to bring down some bungee cords to hold the door on. I could tie or wire it in place, but I have several of those tight black rubber bungees sitting up in the tool shed. They should work just fine. 

Now it's time to fill it. I'll layer all sorts of organic debris. Layering is one of the tricks I use. Grass clippings. Coarse weeds. Young soft weeds. A little soil, usually what's in the weed roots. Manures. Discarded and foraged stuff that the chickens won't eat. Broken up ohia tree twigs. Mushrooms and fungus if I can find them. Urine. Biochar if I have it. Flyblown slaughter waste and roadkill. Enough water to moisten the layers. I try to have a 50:50 ratio of "greens" to "browns", and balance wet stuff with dry stuff so that the pile doesn't get mucky. 

The main reason I use a hot compost pile is to process items that have seeds, possible noxious insect pests, or pathogens (manure). Otherwise using cold composting (my grow boxes) or simply using organic debris as mulch is just fine too. In my taro patch I use trench composting, and that works just fine. But I don't add manure to trench composting since it doesn't heat up. Composted manure is added afterward. 

I'm a big believer in applying compost to the garden beds. It's great for building soil and adding much needed nutrients for the plants. Most veggies really respond well to the stuff. 

By the way, these particular bins are new. My old ones were 5 years old and falling apart. Time to replace them. I've made six bins so far. I plan to make another 6 alongside these, for 12 altogether. 24 hours after making these, bin #1 is already filled. I try to fill one per week. After the 12 weeks that it takes to fill all the bins, bin #1 will be ready to be emptied. It's composted down to 1/4 to 1/3 the original volume. The contents will have cooled off and be partially decomposed. I'll sift the compost through a 1 1/2" grate, using the sifted material in the garden and returning the coarser stuff to the next compost pile. 

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