[redwine@roses]

Has anyone had experience of using gypsum on clay,how much do you apply ,can you plant the ground straightaway,does it work quickly??Help please

[mickeyboy]

Gypsum what you doing skimming it

If you have problems with clay like i do, sharp sand, growmore and a little muck you will soon have nice soil.

Ps is gypsum not a hazard as it is now banned from landfill sites and skips?

[Goosegirl]

Also add some seaweed if you can get it - the gel acts like a flocculant to bind the clay particles together.

[redwine@roses]

Hi Goosegirl,what is aflocculant?

[penance]

Gypsum will help to floculate clay, that is where the small clay particles stick to it making larger particles.
Ground lime stone will do the same.
None of it is an over night cure, breaking up heavy clay takes time and effort.

[redwine@roses]

Thanks Penance for your explanation,can i plant crops with the gypsum just applied?

[zazen999]

It depends on the gypsum.

What are you trying to actually do? Why are you deciding to use gyspum?

[solway cropper]

does it work quickly?

What most of us have found is that there are very few quick fixes in gardening. It's usually a combination of patience and hard work...but don't let that put you off. 

BTW do you mean the raw gypsum as it comes out of the ground or the refined stuff they put in plaster?

[new_2_veg]

Gypsum what you doing skimming it

If you have problems with clay like i do, sharp sand, growmore and a little muck you will soon have nice soil.

Ps is gypsum not a hazard as it is now banned from landfill sites and skips?

yep,

they are treating it like asbestos here and putting it into sealed skips and (im led to beleave) getting burryed in concrete bunkers?

not sure if its a diffrent grade to what would be used on land tho?  know they make mushroom compost with it at snowcap

nathan

[Salmo]

Gypsum will improve clay soils the same as lime but without making it more alkaline.

[zazen999]

Gypsum will improve clay soils the same as lime but without making it more alkaline.

I know that - but I'm surprised at the original poster's almost panicked treatment of soil which cannot be reversed...[My dissertation was on lime stabilisation of soil - but i'd not be chucking loads of gyspum on any soil without plenty of thought and some prior testing]...

[Salmo]

I fully agree with that Zanzen. Gypsum is usually only used in extreme cases such as when fields have been innundated with seawater and the structure is completly gone.

It depends on the gypsum.

What are you trying to actually do? Why are you deciding to use gyspum?

Why do you not answer Zanzen's question redwine? Zanzen is a scientist and is sensibly reluctant to make statements without the full facts. It might also help if we knew roughly where you are. You can easily put that in your profile.

[Faz]

Gypsum what you doing skimming it

If you have problems with clay like i do, sharp sand, growmore and a little muck you will soon have nice soil.

Ps is gypsum not a hazard as it is now banned from landfill sites and skips?

Gypsum is banned from domestic landfills because the bacteria in the waste convert it to the highly toxic and smelly gas Hydrogen Sulphide. it won't do you any harm in the garden, especially if you are using clean stuff that hasn't had paint on it.

[8doubles]

Imo* fluegas gypsum falls into the industrial toxic waste category and is not something i would choose to put on the veg plot.
Have a look at http://www.epa.gov/osw/partnerships/c2p2/pubs/fgd-fs.pdf

If they say one of its main uses will be to stop subsidence in mines it smacks of dumping it out of sight.

* very non-scientific

[JayG]

Faz is exactly right; gypsum as used in the garden is completely safe and a far cry from the flue gas version which is heavily contaminated with other "nasties".

I'm surprised nobody has come in before now and mentioned the useful article on this very site about how and when to use it.

It's here.