Our herb growing situation had been in sad shape for the past six months here at Hyperion. A few years back our friends had constructed a permaculture herb spiral out of chicken wire, which worked beautifully for a while, but became pretty non-functional over time: dirt leaking out the sides, oregano edging everyone out, shriveled up rosemary. My brilliant idea to block access to the spiral with spring plantings had not helped matters. A redesign was definitely in order. Below is the only “before” picture I can find of the spiral- it is the gnarl of chicken wire ensconced safely behind the potato river.
Above is the design we came up with for the herb spiral revamp. The wood along the whole front bed was rotting and had to be replaced, which is what we did first. Below are a series of pictures from the build up, you can click to zoom in. The replacement planks are two 2″x6″ s stacked on top of each other and screwed into 2″ x 4″ stakes every four feet. In the original bed water ran out from bottom of the planks onto the concrete whenever you watered. To address that we sunk the new planks a few inches below the lip of the concrete patio. To ease leveling the boards, and help with drainage issues, the stakes are seated in an inch of gravel. We extended the bed a few feet to encompass the space occupied by the old potato river so we could fit the herbs without uprooting any hot peppers.
Above is a close-up of the herb bed layout. Taller herbs near the center for ease of access, lower growing ones near the edges. The most water needy plants near the bottom, except for the lemongrass which I’m hoping will catch and filter run-off water from the bed above. Below is the bed freshly planted up. Most of the herbs were transplants from the herb spiral and therefore look a little depressed. I’m hoping they will recover or else I’ll have to search for replacements.
To capture rain water runoff I wanted the upper herb bed to be framed by a gently curving berm on the downhill side. Since I also wanted the bed to be narrower and more sculptural than a traditional berm, I chose to use cob for its construction. Cob is a building material comprised of varying proportions of mud, sand and often, straw. Unless protected by a roof or breathable finish cob is vulnerable to the elements. A small, unfinished wall may not last more than few seasons exposed, and even less in climates receiving more precipitation than Los Angeles. But I’ve been wanting to experiment with cob for ages, and as a renter this timeline suits me just fine.
Though we had plenty of clay onsite, we don’t have much in the way of coarse sand so I bought some concrete grade sand from Mortarless Building supply in Atwater. I opted to leave straw out of my mix because all of mine had gone moldy and getting more was too much of a hassle. After doing my best to pick out all the rusty nails and broken glass from the clay I laid what I had out on a tarp and wet it down. Then I stomped around on everything barefoot until it was good and mixed. This process is like kneading bread dough with your feet. The proportions I used were about 2 parts sand to 1 part clay. I probably could have used a bit more sand though, as my wall ended up having some cracking. For such a small project I didn’t bother to make any test bricks, though that is certainly recommended for any higher stakes building. The book The Hand-Sculpted House says that a test for sufficient sand content is to smush a handful of the mix near your ear to see if you can hear the crunch of the coarse grains sliding past each other. Build Your Own Earth Oven is another good book about cob I used.
I only made a small batch of cob, so to stretch what I had, I molded it on top of a form of stacked broken bricks and chunks of concrete. This was also a nice technique for getting the layout of the bed just right, as it was easy to walk around the stacked materials and shift them as need be. Were I to repeat this project, I would sink 1″ diameter bamboo stakes deeply into the ground along the downhill side of the wall before covering everything with cob to further stabilize it.
Here is the finished cob herb bed! Parsley and dill have already been planted. The chamomile is on its way, I planted some in the batch of winter crop seeds I started a few weeks back.
And so you have it, the herb beds as they are now. Maybe those terraces in the background will get completed someday soon. Hopefully before more rains come. Then the allium bed in the design is going in. And the ginger. It is all one step at a time.