I have this one really problematic area at the back of my yard (The Back 40) that causes me no end of grief with weeds, as well as yucky, clumpy soil. Right at the edge of this area (where it sort of branches off from the main yard) grows a thick hedge of Jerusalem Artichokes and a very aggressive hops plant, and sometimes later in the summer I just pretend they’re the edge of the yard and there’s nothing back there so don’t even worry about it, no need to go look at those beds. Last summer I wanted to test a couple of methods to see if I could improve the soil quality in these beds and get rid of some of the weeds in a more permanent way, rather than just pulling them all the time (June-July) until eventually giving up and letting them take over (August) until a sense of crushing defeat settled on me (September).
Method 1: “Solarization”
Solarization is a fancy gardening word for covering up a bed or an area with dark plastic and letting it sit. The theory is that the soil will heat up under the black plastic and cook the weeds and bugs. It is also supposed to speed up the breakdown of organic material, leaving the soil better off.
This is the bed I left to solarize last summer. In the spring, I dumped the ashes from my firepit in it because that seemed like a good idea at the time*, and then I covered it with a dark tarp in the hopes that the thousands of weeds in it would die and the bed would emerge the following spring like a beautiful composted phoenix. Today, I pulled the tarp aside like a magician to reveal what is underneath:
- The ash did not decompose whatsoever, it seems.
- There was a large area that had been colonized by ants. (Thus the diatomaceous earth you see sprinkled along the top of the bed. Does this even help? I don’t know, but it makes me feel like I am at least doing something.)
- It did seem to help with the weeds. Almost none were growing, and the few quack-grass clumps that were there were very close to the surface and easy to pull. They also looked pale and unhealthy, like vampire quack-grass. This made me feel like I was killing them slowly by starving them, which was very satisfying.
I think this experiment did help with the weeds, but the soil quality/clumpiness/clay-y-ness didn’t improve noticeably. Today I added some composted manure and worm compost and dug it in, then covered it back up with the tarp. No point in letting it get full of weeds again before I get a chance to plant it. I know if I leave it unattended for 48 hours, this will happen.
*I realized soon afterward I probably should not have done this, since we burned some of those chemical-y firelogs at a few points in the past in the firepit (although a long time ago) and it’s probably all full of chemicals now. Also, you are not supposed to do this without a soil test first to check your soil’s pH. Do as I say, not as I do.