[Steveharford]

I've got a lot of off-cuts of plasterboard from a job I'm on and I'm considering incorporating them into my clay soil to help break it down. As far as I know it's just paper and gypsum. It also crumbles easily when wet so would soon break down especially if I bash it a few times with the rotovator. Can anyone see any snags with this?

[barley]

as far as I know  plaster is rich in lime and paper should mulch so can't see why not

probably a EU law or elf and safety says NO !!!    ok to put in land fill though 

[Totty]

Too much lime in your soil will alter your ph, this can lead to nutrient lock up, meaning plants can't make use of nutrient in the soil, even if there is plenty there. Lightly dressing with lime before some crops is often advised but there is no need if the ph is right. Negative side effects will probably not be noticed until three years after application, but I'd suggest adding loads and loads of organic matter as opposed to turning a load of plasterboard in though.

Totty

[Steveharford]

Lime plaster is a completely different thing, which definitely has a high percentage of lime and sand. Also often horse hair. As far as I can gather, the main constituent of plasterboard is gypsum which is neutral ph. But are there any other additives I wonder. I suppose an email to Lafarge or similar might get that answer. Oh and one of the reasons I am looking for a use for it is that it is no longer permissible to dump it in a skip. At least not mixed in with other rubbish; it has to be kept separate so that it can be recycled. That is, it can be bagged up and put on the top of the skip. Skinflint !

[Trillium]

Over here gypsum is sold as a clay soil loosener. Clay soil tends to be more acidic as well so a bit of lime helps out.

[Goosegirl]

As Trillium says, gypsum is good for combining the tiny clay particles into a bigger-sized one to aid drainage etc. You could always buy one of those pH tester kits to give you an idea of how alkaline it is.

[Steveharford]

Just looked up the constituents of plasterboard on my coffee break between battling with the rotavator.    It appears that there is a little lime present but shouldn't do any harm:            Gyproc plasterboards are not classified hazardous under CHIP 2M Regulations 1994 (refer to section 15). General composition: calcium sulphate dihydrate encased in paper liners. Natural constituents may include clay, limestone and minor amounts of quartz. Minor additives may include starch, foaming agents and dispersants.