I really miss California. Growing up there deeply shaped my preferences as a gardener. My favorite flora all tend to be mediterraneanish in nature – lavender, rosemary, citrus…. olives.
Oh, olives. I love everything about olive trees – the gnarly stubbornness of their trunks, the slender shape of their foliage. The silvery color of their leaves, their smell. And the olives? Oh lord. I could eat olives pickled, brined, dried, canned, you name it. I have a deep appreciation for the complex flavors of olive oil and I would totally shoot it once in a while if it were socially acceptable (shh, don’t tell my friends).
But growing olives in Maryland? HA. We’re 1 1/2 zones too cold have a hope of most olives surviving here… or so goes the conventional wisdom. But then I started hearing about this particularly cold-hardy olive, the Arbequina, and how it could be grown in zone 7. That if you could protect their roots they could survive down to 10*F or so.
Enter the last un-terraced part of my steep southern-facing slope.
You see, I’d spent most of last year researching sustainable building methods such as Earthship and passive greenhouse construction. (If you’re not familiar with Earthships, they are amazing. Entirely self-sustaining, built from recycled materials… check out the video below.)
I got so excited to build my own greenhouse using these Earthship techniques. Plans involved recycled tire walls for thermal mass and aluminum can knee walls for insulation, not to mention rainwater catchment and an in-floor rocket stove. Then I ran into problems with the gritty reality that is architectural drawings and local permits and red tape… things ground to a halt pretty quickly. I was more than disappointed and turned my sights to other things.
But all that research wasn’t a complete waste of time. Searching for a solution to this problem I realized I had a southern facing exposure with a steep, nearly wall-like hill for thermal mass behind it. The shed to the North blocks the coldest winds and reflects more southern sunlight back onto the hill. It dawned on me that I had a tiny microclimate on my hands – one that with a little extra manipulation might just be warm enough to keep an olive tree alive through a normal Maryland winter. If I could insulate the roots I might be on the way to an actual, possible solution.
I knew from my Earthship research that air is a fantastic insulator. Aluminum can walls are really great to build walls from because each can, stacked in a honeycomb fashion with cement between, traps a little pocket of air. So what you end up with is fantastic insulation built right into the wall using only trash.
You can do the same thing with 2-liter bottles and cob (adobe), and there are permaculture groups in places like Haiti promoting this form of building to those with no housing or access to lumber. A solution to aid those that need shelter and clean up the planet at the same time? Pretty neat.
People also build walls out of glass bottles using a similar technique – though generally they use wine bottles with lots of colors because if you leave them uncovered on both ends they act like little stained glass portholes through the wall.
I wasn’t really interested in their beauty though. I only wanted insulation from free, recycled building materials. Why not take advantage of my husband’s love of beer to build a super-insulating wall with all those unattractive brown bottles? Maybe their dark glass would even help warm stuff up a bit, I don’t know.
But apparently I got so excited to start that I forgot to use my level. Sigh. Oh well – I really was going for an organic, curvy, handmade sort of look. (Maybe just not quite this much.)
ARCHITECT-Y, ENGINEERING RELATIVES OF MINE, AVERT THINE EYES.
By the time I noticed, the concrete had firmly set all the way down to the levels buried below grade. I had even done a careful job of embedding lots of chicken wire to tie all the levels together, so now it was all just one big block and I had no choice but to continue. Believe me, I thought about demolishing the whole thing, but didn’t relish the thought of thousands of glass shards in the garden forever.
Resignedly moving ahead, I bought a sheet of diamond mesh. I figure if I’m careful to set every bottle so its end is flush to the mesh or at least touching it, it ought to help guide my curves and slope… right? I did use my level carefully in subsequent layers, but in order to level it back out in the first place I had to smoosh in a whole bunch of concrete. So it’ll probably look like a wobbly concrete sandwich and be super noticeable. Grumble. Maybe I’ll just, like, plant some bushes in front to hide it. Or something.
I carefully plugged all the bottles with cement so they wouldn’t fill with dirt. Except those bottles on the bottom 3 layers – those, I want to fill with mud and dirt in order to act as anchors. I angled the bottles on the upper layers slightly tip-downwards so that if water does seep in, they can drain.
It’s nearly twice this tall now. But the day after we used up the last of the beer bottles I taken months to collect, freezing nights set in. No more concrete work til next year, I suppose.
So. This little wall sure ain’t gonna win any beauty contests! But I’m still just ridiculously excited to keep working on it and explore its potential. If it turns out that it doesn’t work as insulation, well, that area needed some terracing anyway. If it turns out to be too ugly even for me (which is saying a lot!) I can face the whole thing with stucco and hide it away like a guilty little permaculture secret.
But here’s hoping it won’t come to that!