Topic: Gypsum

[Common_Clay]

Hi,
  I was recently recommended by a fellow plot holder to sprinkle gypsum onto freshly dug soil. We have a heavy clay soil and he had very roughly dug fallow ground into big clods and said that a sprinkling of gypsum on it like that would turn the soil into a beautiful texture by spring next year. He swore by it and said it was sort of like lime but much better, but I'd like to hear anyone else's comments on this before I go and add anything I'm a little unsure of into the ground... this is the first time I've heard of its use in this way.

Thanks in advance.

[saddad]

I have heavy clay and have several testimoials from the old guard that it works wonders but haven't used it myself...
 ::)

[Common_Clay]

Thanks saddad, at least it's known of then!

Can anyone think of any downside to this? I don't know too much about the properties of gypsum, any nasties?

[jennym]

The Environment Agency advice has been that no more than 250 tonnes per hectare be spread in any 12 months, but there is a consultation document in hand which may review this. My maths isn't brilliant, and I calculate this to be 2.5 kg per sqare meter, which seems a lot to me.
Some reading here:
http://www.allotment.org.uk/articles2/Gypsum_Valuable_Input_for_Agriculture.php
http://www.lafargeplasterboard.co.uk/drywall_manual/pdfs/Health_and_Safety/Health_and_Safety_Sustainability.pdf
The relevant legislation is: http://www.opsi.gov.uk/SI/si1994/Uksi_19941056_en_5.htm
What I would say is though, that do make sure you know for certain that it's plasterboard waste you're using, and not something awful like asbestos waste (which can look similar).

[supersprout]

Love to get chapter and verse Jen! ;D
Hi CC the regulars here swear by it too for some of the patches of clay.
It will make your soil more alkaline - good news for brassica, not so good for spuds :-\
Could you get organic matter onto your plot instead to improve the soil?
SSx

[Robert_Brenchley]

Gypsum in small quantities occurs naturally in many clays. I've often heard that it will improve clay, but never having gardened on the stuff, I don't know for myself.

[Common_Clay]

Thank you so much jennym, very helpful. I haven't read through it properly yet but I will when I have more time.

SS, I would love to add organic matter to improve the soil but having a bit of trouble working out what to do. We can no longer get manure deliveries to our plots since the previously vacant plots at the bottom of the allotments were used by the tractor delivering it but they're now in use.
  My compost bin is absolutely nowhere near composted and even if it was it wouldn't go far. Buying the stuff is too expensive.  ???

Thanks again to everyone.

[Robert_Brenchley]

Another use for gypsum I came across while preparing a lesson earlier is to remove salt from soil.

[triffid]

This from Henry Doubleday Research Association to add to your growing stack of info, Common_Clay  :)

Gypsum is acceptable for organic gardening

Major nutrients = calcium sulphate (S 13%, Ca 16%)

Supplies calcium without altering pH

A gypsum:dolomitic limestone mix (80:20) can be used to help lighten heavy clay soils.