I have heavy clay soil. I just discovered that drywall is compostable, and possibly good for certain types of soil (like heavy clay).

I can break it into sufficiently small pieces with a hammer, but doing so directly on top of the soil actually compacts the soil more. Breaking it on flagstones damages them, too.

Is there a safe and somewhat easy way to break up drywall without causing collateral damage?

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    Take a look at my comment to Bamboo and read this MSDS information. DO NOT whatever you do CRUSH this stuff without a REAL AIR FILTER RESPIRATOR. lafarge-na.com/MSDS_North_America_English_-_Drywall.pdf
    – stormy
    Mar 18 '17 at 22:22
  • Thanks @stormy. I'm well aware of the health risks and/or precautions. If you read the article I linked, it suggests large chunks work as well as fine dusted stuff, so I'm planning for the former (less work than grinding).
    – ashes999
    Mar 19 '17 at 1:22

Ashes! NO you should definitely NOT use drywall/plaster board in your soil!! It is gypsum as well as all kinds of petroleum and chemicals NOT good for soil, especially clay or soil you want to grow edibles!! Do you remember the site you read or where you got THAT information? Please send it if you are able.

Here is the absolute truth; the ONLY way to improve ANY soil is to add DECOMPOSED ORGANIC MATTER. The key word is decomposed, already been broken down by decomposers. That matter is what 'feeds' the micro and macro organisms in any soil. These organisms eat this stuff poop it out and mix this stuff into the soil for you. As long as you've got only decomposed organic mulch it is used immediately and these organisms go out to tell their friends and multiply like crazy. Plants and these organisms need each other. This decomposed organic matter as well as the pooped out stuff adds the necessary TILTH for porosity and holding air for plant's health. No matter if you've got sand, silt, loam, sandy loam, clay or clayey loam, etc.

Think about how concrete is made; sand, gravel, gypsum, lime, water and CLAY. Then rotation and mixing is added. Clay is a very cool soil. Most of my experience has been with clay; blue clay, caliche clay and all of it all I used was DECOMPOSED organic matter...and fertilizers as needed for the particular plants planted. I add lime ONLY when I want to raise the pH for certain plants and that is ONLY after viable tests. The only time I add elemental sulfur is when I want to lower the pH ONLY when I know the original pH for a particular plant or crop.

Clay is the tiniest of the little rocks that make a soil. They are also FLAT. This gives them an electrostatic charge that HOLDS the particles together, necessary for concrete. You never want to ever rototill and manipulate clay, especially WET. Just dig and dump, slightly chop...look up 'double digging and raised beds without any construction'

That is it! I'll never add anything else...double dig your soil and throw in DECOMPOSED ORGANIC MATTER, (not just organic matter, decomposed or the immediate decomposers will gobble up any available nitrogen to do their work and the important micro and macro organisms go dormant until the non decomposed organic matter is decomposed so that it is then available to the soil organisms for food. Raise your beds. Provide trenches for drainage. And often just add decomposed organic matter right to the top of your soil. The organisms come up and eat it, go back into the soil profile to poop it out continually improving your soil!

Take the drywall to the dump in the construction debris section!

my caliche clay garden first year another image of caliche clay garden first year

This is almost 70 percent clay. When it gets wet it is as slick as snot. I simply double dug the beds, turning the soil over, allowed the soil to dry for a few weeks, and put decomposed horse manure on the surface. Then again for the winter. I'll do this for at least 5 years on this soil then I'll cut back. There is such a thing as too much! But I got great crops the first season. Never use a rototiller on clay.

vegetable beds with volcanic pumice, virgin forest soil

Soil does not come with 'nutrients' for plants. One needs to KNOW how to manage their type of soil. A soil test is critical at least just ONE professional soil test. A second would show you the changes and if you've over fertilized. The only way the necessary chemistry for plants a human wants to grow for their own agendas gets in the soil is if WE add it. Compost is not fertilizer. Added hot perhaps a bit of nitrogen. Problem is, nitrogen is the primary 'food' for decomposers. Decomposers get first dibs on nitrogen when they do their job. Literally insignificant nitrogen if any is left for plants.

Drywall is NOT good for the soil. Rototilling is the worst thing to do with high clay soils. Gypsum + Lime + sand + gravel + clay + water + rotation = concrete

The problem we are looking at is the age of YOUR drywall. If it is older than 2016, there might even be biocides (killer of life), sulfur which will make your soil acidic and other funky stuff.

The worst part for humans is breathing the drywall dust.

composition of drywall

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    The link provided in the question leads to an article about composting unpainted untreated drywall, Stormy - but they composted it with other materials. If the article is right, it's a suitable material for composting, have a look...
    – Bamboo
    Mar 18 '17 at 21:11
  • I'll take a look, Bamboo. But what I know about drywall and the chemicals for fire retardants and mildew retardant...lath and plaster were fine to compost but I'll have to update me knowledge, and get back to you and OP.
    – stormy
    Mar 18 '17 at 22:08
  • lafarge-na.com/MSDS_North_America_English_-_Drywall.pdf Here is the MSDS sheet on drywall of today. The biggest danger is crushing, pounding and inhaling the silicates. Not so very simple. Be a great idea but take a look at the additives for fire retardant and mildew. And guess what, they mix crushed drywall with my beloved biosolid, Gro Co. No wonder their tests come up looking great. Not a suitable material in my opinion for composting. Ugh!
    – stormy
    Mar 18 '17 at 22:20
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    Well, I'm glad I asked. Even if the gypsum one is safe, there's no guarantees the others are safe. Thanks for the link; I don't know if mine is LaFarge or not, but it's certainly not worth the risk.
    – ashes999
    Mar 19 '17 at 1:24
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    My comment was simply to point out that there was a link to the information within the question, given you asked for that info in your answer. Personally,, I'm about as likely to add drywall to a composting system as I am to turn back into my 25 year old self overnight...
    – Bamboo
    Mar 19 '17 at 13:03

I put dry wall ( aka -gypsum) in a large clay and gravel garden . I got "bearing strips" in a rail yard at no charge. Bearing strips are about 6" X 48" so they were not big pieces. I put in a lot ( one ton +) in about 100 sq yards of garden . I spread them around by hand and after a couple rains ( no dust) I brought in a secret weapon ; a Gem rototiller ( made in the UK using a 20 Hp Wisconsin engine).The rototiller broke up the drywall as it mixed it into the soil. The paper on the drywall was a little problem , for months I picked the 6 X 48 paper strips out of my and neighbors yards. I also added tons of organic material ( spent mushroom farm synthetic manure) . Things grew well but I can't say what helped the most.

  • I can't imagine that dry wall was in anyway a positive thing for the soil. Rototilling is contraindicated for clays!! Dry wall is full of other chemicals that are NOT beneficial to plants nor the life in the soil.
    – stormy
    Nov 30 '19 at 3:02
  • Drywall is primarily gypsum/calcium sulfate. The sulfate should gradually release and the acidity loosen up the clay . There is already Ca there so more Ca has little affect. Dec 2 '19 at 20:11

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