Urban Projects — by Mark Feineigle January 25, 2013
Continuing from my last post, after cleaning up our yard and several neighbors’ yards from another unusually strong storm here in south western Pennsylvania, I had a cache of branches to utilize in my garden construction. Our summers here have been getting hotter and drier so I wanted to take advantage of wood’s ability to help retain moisture, coupled of course with a blanket of straw to further retard evaporation.
Flashing was placed on the lower portion of the shed to prevent rotting from the bed to be built around it. The bed is kept away from the shed wall by about 100 mm (4 in) to allow some degree of ventilation and the two sides of the shed that do not have beds installed are open and face the predominant winds.
Heat treated pallets were cut to provide durable stakes to hold the walls together. Simply plan out the outline and pound the pallet shards into the ground to form a channel. Fill the channel with sticks, taking care to weave the corners together. Once the first section was complete, I filled the rear wall with sifted clay to help form another barrier to prevent any decomposition from taking place too close to the foot of the shed.
The bed was then filled with lasagna layers. First, unruly ends of logs were placed on the bottom to act as a sponge, hugelkultur style. Next newspapers, finished and rough compost, grass clippings, and straw were added to fill. These are decomposing now over the winter and should provide very fertile grounds come spring.
Cardboard was placed between the wall and the decomposing materials within to help slow the wall’s decomposition. You can see here that the larger branches form a ‘cleaner’ wall than the first one, built with lesser diameter sticks. Since this was a learning process I wanted to save my better materials until I had some practice building the first section.
More lasagna layers were added, still making sure to pack the area between the wall, now lined with cardboard, with straw. Again, to slow wall decomposition. You can’t see it in this picture, but as each layer of straw was placed, I simply packed a few extra handfuls around the edges.
Here you can see the space between the bed and the shed, maintained by a few 100 x 100 mm (4 x 4 in) boards.
The grass around the bed was covered in newspaper and straw. A seasoned section of tree trunk was placed in the larger bed to act as a sponge as well as allowing one to lean into the bed to easily reach the back.
Another layer of compost and straw were added as the initial layers broke down; this last picture is not full. I expect to have to add another few layers come spring.
After using most of the better branches, I was left with a large number of smaller and/or crooked sticks. While the smallest were a welcome carbon addition to my compost piles and carbon lasagna layers, I wanted to get more use out of the others.
First, sticks were roughly laid out to mark several contiguous keyhole beds.
The heavy clay soil was turned over, chopped up, and amended with several handfuls of gypsum.
Layers of fresh (within a few days) cut grass, newspaper, and compost were applied. 450 mm (18 in) long sticks were cut and driven in around the beds every 450 mm (18 in).
A layer of straw was added and the less desirable sticks were strewn roughly between the layers and the sticks, forming a primitive wall. The sticks were overlapped and interlocked together quite nicely; the wall is much sturdier than I would have imagined.
A small amount of newspaper and compost were added, taking care to leave another buffer of straw directly next to the wall to help slow the decomposition of the sticks forming the wall. Lastly a final layer of straw was added. I call this the Leaf Bed because the final shape looks like a leaf with veins as walking paths.