|The new compost pile is covered with a tarp to keep moisture in. Eventually it will fill this whole space. In the background you can see our leftover adobe bricks.|
So–our regular readers will know that we have high levels of lead in our back yard soil. We’re dealing with this by filling most of our yard with mulch and perennial natives to lock down the soil (lead laden dust is bad) and to diversify the local ecosystem.
Meanwhile, our vegetables must be grown in raised beds from now out. We used to have two main vegetable beds in the center of our back yard–they were our workhorses. Since the lead scare we’ve pulled up those beds. They were semi-sunken beds, the soil in them a mix of native soil, compost and imported soil.
When you have contaminated soil yet want to grow food, the easiest solution is to build extra deep raised beds and fill them with imported soil (soil which has, hopefully, been tested for lead!). Some people put plastic sheeting or rock barriers between the imported soil or native soil, which in effect makes the beds into giant containers.
We did something a little different–and a lot harder. We dug out a huge pit where our beds used to be. When I say “we,” I mean Erik dug a huge pit. (Somehow I weaseled out of this project.) This excavation had two purposes: 1) to remove the topsoil, where most of the lead (lead being an airborne pollutant) is located and 2) to harvest the clay beneath to use in our earth oven. Between the clay harvested for making the adobe bricks and cob, and the supplemental clay that we’ve put aside for future repairs and maintenance on the oven, the pit has grown to be about 12 feet wide and 2 feet deep.
This pit is going to be our new planting area, but obviously it needs to be filled in. Instead of buying imported soil, we’re going to grow soil by composting on a grand scale. We’re going to compost right in the pit and fill it up bit by bit. When it’s done, we’ll have a big round area where it will probably be safe enough to plant food crops. Might the plants suck some lead up from the deep clay layer? Maybe. We could test the deep clay. Might some lead leach in from the sides of the pit? Possibly. But this solution is good enough for us.
What drives us to this decision is our intuitive relationship with our yard. I know that sounds a little woo-woo, but I encourage you all to pay attention to what your gut tells you about your gardens. It won’t steer you wrong.
Our gut instincts told us to dig down rather than build up, and to make good use of excavated dirt in the oven. Now our instincts tell us to fill this giant hole with rich homemade compost rather than imported soil. It just seems more…holistic to grow out own soil. It will rise out of our meals, our labor, our intentions. It will belong to this place.
How long will this take? Probably about a year. Maybe more. We’re willing to wait for those future harvests because this feels right.