Heavy Duty Wood and Ratwire Bin
This compost bin is designed to be expanded with the size of the garden or yard waste load. It can be made as a single 4 x 4 x 4 compost bin and then later additional sections may be added. A single section will hold about 50 bushels of organic material. A three section system will hold 150 bushels, more than the volume of yard waste produced on most homes with less than 1/2 acre of land.
[Line drawing - Heavy Duty Ratwire Bin]
This bin is permits access from the front or the back, a feature that is convenient if the bin is located in or close to a large garden. The sides of the bin are made of hardware cloth, and the removeable front and back are made of boards that have air space between them. This design allows sufficient air to get to the pile.
The strips used in the guides for the front and back boards require sizes not found in normal lumberyard stock. If you have a table saw or if you have a friend who has one, these pieces can be made easily. If you don't have that tool, you can have the lumberyard cut these pieces for you.
There is no cover included in this design, to keep it as simple as possible. There are many ways to cover the pile, the simplest being to lay a piece of plastic film over it. Any kind of material that will keep the rain off a working pile is satisfactory in this system.
The specifications below are for a compost bin with one section. The design is laid out so that one, two, or three sections can be constructed. The expansion of this design to fit your volume of yard waste is essentially the same procedure described below. Be sure, though, to build the single section bin with at least one side having the double-sided guides so that it can be expanded later.
|4 x 4 x 12 foot pressure treated timbers
|1 x 2 x 8 furring strips
|3/4 inch x 1 inch (actual dimension) board--4 feet mimimum length
|1 x 6 low grade planed boards (in 8-, 12- or 16-foot lengths)
|18 feet x 24 inch hardware cloth 1/2" mesh
|common nails 6d
|finish nails 4d
|galvanized nails for guides 8d
|gun-type staples for hardware cloth 9/16"
|1 small roll of annealed iron wire
|Main vertical post
|top pieces of frame
|side pieces of frame
|front and back guides
|bottom stop blocks
|end post guides
|1"x1 1/2"x 4 feet
|center post guides
|hardware cloth divider panels
Tin shears for cutting hardware cloth
Note in the illustration that the end frame and the middle frames are different in their system of guides for the front and back boards of a three section bin system. A three section compost bin would have two end frames and two middle frames.
The guides for the front and back panels are fastened to the 4x4 posts. The illustration shows that the end frame guides have right and left sides, while the sides of the middle frame guides are the same.
1. First assemble the two side panels and attach the hardware cloth along the edges of the wooden frames with a staple gun.
2. Then dig the holes for the 4 x 4 corner posts. The sides are located at a sufficient distance from one other that allows the wood panels that form the front and back of the bin will slide smoothly in the guides.
[Line drawing - Side Panels]
2. To build the guides for the wood panels tack a 3/4 x 1 inch wooden strip along the outer edge of two 4x4 posts, according to the illustration. Make sure the 1 inch dimension is vertical to the post so that there is sufficient clearance for the 3/4" sideboards to slide easily. Then nail a 4 foot piece of furring strip over the 3/4 x 1 inch wooden strip and through into the post (use 8 penny galvanized nails). You may wish to drill guide holes for this procedure to ensure having the nails go in straight and to prevent splitting.
3. Fasten a stop block at the bottom of the guides on each post so that the sidehoards wil all be even when they are inserted (see illustration ).
4. Next Make The Frames - Make the basic frames for the hardware cloth by attaching two 3 foot 8 1/2 inch furring strips on to two 4x4's. Then connect two 4 foot furring strips at the top and bottom creating an almost square frame. Next staple the hardware cloth onto this frame. For best results for this procedure, use an awl to stretch the hardware cloth diagonally after you staple the first side. This eliminates any bulges in the cloth.
You may have to use two pieces of hardware cloth to cover the frame. In that case, use flexible soft wire to weave the wire between the two pieces of overlapping hardware cloth that are attached to the frame. This will keep the hardware cloth from separating and bulging when the bin is filled.
5. Erect the frames in the ground. The main concern is to ensure that the frames are at the proper distance from each other while being in line and level. This is easier said than done.
6. Install the frames one at a time from one end of the structure. Dig two postholes 2 feet deep and set the first hardware cloth frame into the holes. Make the it level and vertical sideways and front to back, and then fill in the holes with some rocks and soil, tamping as necessary.
7. Using two sideboards at ground level, locate the next two holes. Dig those two holes and install the second hardware cloth frame at the proper distance so that the sideboards have about 1/8 inch clearance at both ends. Again, make this frame level and vertical and then temporarily nail sideboards at the top and the bottom of both sides of the two frames. If you are building a three section bin, continue with this procedure to install the last two sets of frames. Leave the nailed boards at the top and bottom in place for two or three days to make sure that the posts have settled properly.
7. Slide the boards into place to form the front and back panels of each bin.
6. When the bin is filled to the top with organic material, the two sides may, over time, tend to separate even with posts dug down two feet into the ground. To solve this problem, attach a wire to a spike hammered into one end post and run it to the other and attach it to a small turnbuckle fastened to another spike in that post. This device makes it possible to tighten the wire and counter the pressure of the heavy compost against the sides of the bin. Put this wire rig on both the front and the back of the box. (see illustration).