digging up bricks and cement

Hi. I'm starting out and digging up a patch of lawn to make a vegie garden. I'm in NZ and following set up guidelines from Kay Baxter which involve double digging rather than a no-dig setup. However we've discovered a path and bricks set in concrete / cement under the lawn. I think an old garden shed used to be in this spot. Should I avoid this spot after all? Do you think it is likely to be contaminated by toxins? I'm just looking for a comomon sense answer here so I don't do something that would be clearly stupid. One day I'll do a soil test but it costs about $200 so I'm going to postpone that for now.

Hi, Carla, and welcome to permies!

Without a soil test or any solid history of what structure used to be there and how it was used, there's really no way to say about toxins. Your guess is as good as anybody's here on permies. But if it was "under the lawn" and the grass was growing evenly, it's not a thing I would worry about. (Other people here on permies worry about toxins more than I do, and they may tell you a different opinion of course.)

Mechanically speaking, you may be in for a ton of work trying to dig out bricks and concrete. But you may be able to salvage some of the bricks for use as bed edging or whatnot.

Good luck!

There's no telling what might have been in that shed, if it was a shed, without a test looking for persistent chemicals and heavy metals. That said, it could have been a chicken coop!

Are there places in the lawn where there are not any bricks/concrete underneath? If there are, do you see any coloration differences in the grasses or broadleaf herbs that are growing there as opposed to over the bricks? If the plants look as healthy over the bricks, that can be a good sign; but is definitely NOT definitive of purity.

All of that said, plenty of gardens have been built in worse situations.

The quality of living soil you produce, especially with organic matter (humus), and mycorhizal fungi, will aid in decontaminating/immobilizing hazardous products in the soil.
Good news story you should read to keep your spirits up about what is possible: How Mushrooms Can Save the World!


Do you have the ability/tools to break up the concrete into useable sizes? What I'm getting at is that you could smash it with a sledge, or a pick, or a rented jackhammer, and break it into pieces you can handle---permies call re-usable concrete 'Urbanite'. Urbanite is a resource. It is easy to stack urbanite and it often can be broken with a straight-ish edge and can thus be used for building garden walls, or even houses. Everything is a resource/opportunity.

I hope this is helpful.

I see Dan piped up while I was writing! Awesome! Yes; though I can occasionally freak myself out about toxins here and there, I generally let nature take it's course and trust my soil and my body to deal with it. When I consider the crappy food that i grew up eating, and the toxins that I have put on my skin on purpose, and that I am pretty healthy now at 46, I figure there are worse things in the world that could kill me. I just work hard at making things as good as I can.

Well thanks for the encouragement. Hubby is doing the digging and the pile of concrete lumpsgrows. Most of the bricks are intact and beautiful old bricks I read that article on mushrooms....that was great and yes very hopeful. Its good to hear about positive news rather than environmental collapse.
Thanks heaps.

My garden was the same- everywhere I started to dig I found concrete, bricks, roof slates, etc!

After trying to plant a tree- what should have been a simple 12" hole that ended up with me excavating several 5ft concrete fence posts... I gave up. I resorted to raised beds instead, just growing my veggies on top of the bricks!

I made mine from old scaffold boards, they're about 25cm deep. Of course you have to find all the matter to fill the raised beds- but it has only taken me 3 years to fill 5 raised beds (25cm deep, 4.8m long and 1.2m wide)- with grass clippings, hedge trimmings, next doors veggie trimmings, shredded paper, leaves.. etc