Old lime mortar as admixture in clay soil?

[Wayne Whitney]

The soil in my area (Berkeley, CA) is clay, which I understand is usually acid (I'll check mine with a pH test). I have a bunch of old (1910) mortar from taking out a chimney (seismic concerns) and cleaning off the brick for reuse. I understand old mortar is usually just sand and lime, so it seems like this would make a good treatment for acidic clay soil. Would it be crazy to spread this over my yard and mix it in? I'm going to be re-landscaping most of the lot (1/8 acre) anyway.

Thanks, Wayne

P.S. I understand that most wallboard is just gypsum and paper, and that gypsum is also good for acidic clay soil. What is a good way to grind up wallboard scraps?

[Richard J Kinch]

Not enough material to make a difference in any case.

No, it typically contains fiberglass today, or asbestos if it is older, not a good thing.

[Sunflower]

Most CA soils are highly alkaline. Not a good idea to mix in lime. And, even if the soil were acicid, mixing in chunks of hardened cement still wouldn't be a good idea. Ever try digging someplace that has a high rock component? Not easy at all, and you want to create that in your back yard?

[Tom Baker]

We happened to mix in a lot of old plaster with our soil and the plant growth was excellent. We didn't do any thing special. TB

[Wayne Whitney]

Good to know, I will certainly check my pH first.

True. But old mortar (pre-1930 ?) has no cement, it is just lime and sand. Most of what I have is crumbled up already, I'd put it through a sieve first.

Cheers, Wayne

[Richard J Kinch]

A negligible less than 1/100th of your topsoil.

Snap a piece and you'll see by the "hairy" edge that it's throughout.