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Ontario, Canada.

1. Gypsum in garden centers is hard to find. Can I use the bagged gypsum Home Depot sells for drywall mudding?

2. Epsom salts. I also had some yellow leaf problems with Lan2 this spring. How much epsom salts should be applied? Fall or Spring.

Russ L.

9/24/2003 9:23:22 PM

Menomonie, WI (mail@gr8pumpkin.net)

Nooooo, the gypsum in drywall mudding is not for agricultural purposes. \
What is your P.H. at? Shannon

9/24/2003 9:31:40 PM

Ontario, Canada.

Still waiting for first test result. Suspect it is below 6.5

9/24/2003 10:02:24 PM

Ctpumpkin@optonline.net

Wait for the soil test. Gypsum is a lot like lime but non reactive so it doesn't alter pH. If if your pH is low & you have to lime, then you likely also won't need Gypsum unless your Ca is crazy low.

Mg is alailable in Dolomitic Lime. So if Mg is low, we'll get some there too. This would negate the need for Magnesium Sulfaqte (Epsom Salts).

That said, we're striving for a balance between Mg, Ca, & K. Blindly applying one without knowing the values of the others could upset the balance.

In other words I could have less Mg in my soil than you, but have no need for more because of my Ca & K levels. Likewise you could test high & still need to apply more to compensate for other elevated values that are knocking your Mg from the soil cation sites. Balance.

Let's look at the printed soil test results when the get back.

Either way. Drywall compound is for drywalls.

Steve

9/25/2003 7:39:11 AM

Caceres, mid west of Spain

I used drywall gypsum on the soil several times and it worked very well.

Carlos

9/25/2003 11:11:18 AM

Ontario, Canada.

Well, now I have two different opions on drywall gypsum?
who is right?

9/25/2003 12:57:27 PM

Ctpumpkin@optonline.net

The material I find at the local Home Depot contains something that makes it as hard as a rock. Ag gypsum doesn't get that hard, I'll snoop around as time allows & find out what they add to it. There might not be any danger to it. But I can say for sure that I wouldn't be caught dead try to spread the stuff. It's about as fine as talc. The pelletized Gypsum we sell is very easy to handle & spread. - Steve

9/25/2003 1:19:43 PM

Ctpumpkin@optonline.net

Clipped from Cornell University from an article discussing the problem with drywall (gypsum wallboard) waste from construction.
________________________________________________________

One favorable alternative for drywall waste that has been studied extensively is to use it as a soil amendment. One study found that applying pulverized drywall waste to soil on a plot in Upstate New York had a beneficial and non-detrimental effect on the soil and a positive impact on corn production. A recommendation from this project was that a similar study should be conducted on a range of soil types to develop a data base on effects of gypsum waste on different soils. Another recommendation was that pulverized gypsum waste could be applied to roadside soils in Northern climates because of benefits for those soils that have been affected by salt used during winter seasons.



Some concerns about implementing programs that use drywall waste as soil amendments have to do with different drywall types. Fire resistant drywall, for example, has fiberglass in its composition; asphalt-based wax emulsions are used in moisture resistant drywall. These are not regarded as favorable soil additives. These concerns could be addressed by limiting drywall as a soil amendment to regular drywall, but effective limitations would require strict controls.



More research is needed on the issue of drywall waste. Growing public awareness of this issue may lead to the development of additional options for re-use or recycling. In the meantime, research could be encouraged to investigate feasible methods that can be used at construction sites to reduce the amount of waste drywall that is being generated.

http://www.human.cornell.edu/dea/extension/docs/sum96/wasteman.htm

9/25/2003 1:47:02 PM

Oz

i used epsom salts..a handfull to 40gal water...
it didnt hurt,,,,

most drywall dust/mud have silicates in them and poly fibers,,,etc...not good for soil,,,
look for a gypsum mine near you...
im sure you can get pure gypsum from the drywall mfg,,,
id mix it with lime and a little water..and peat,,,,

9/25/2003 1:51:01 PM

Ontario, Canada.

It seems like the jury is still out on this one. More info is certainly required.
Thanks all for your help so far.
Russ L.

9/25/2003 3:55:06 PM

Ontario, Canada.

Epsom salts. I found some info last night that said 1Tbl spoon to the gallon. Mcpumpkin I figure you are about right. One issue is resolved.

9/25/2003 3:57:48 PM

my unknowledgable opinion:

it's DRYWALL stuff, not PUMPKIN stuff. go to the greenhouse jeez people.

9/25/2003 7:01:15 PM

Montoursville, PA

Gypsum is gypsum. The agriculture products have sulphur added to bring them to the ballance that will not alter PH, in your patches. Gypsum without the sulphur will have a liming effect and may tilt the scale unless you are fighting an acid patch anyway.

The original question had nothing to do with crap coming out of remodled or trashed buildings. Simply don't use the waste stuff. You do not know what is in it.

9/26/2003 2:34:20 AM

So, can I just go to a home depot store and buy gypsum that is labelled for building and modelling and use it for my pumpkin patch? I can't get agricultural gypsum anywhere. I've already asked in many garden centres, farming supply stores, etc. but found nothing.
Hey, all you German growers (Owen, Ingo, Werner, Michel) out there! Have you any ideas where we can buy agricultural gypsum here in Germany?

9/26/2003 6:50:09 AM

Knopp, Germany

No Martin I don't. Did a internet search, nothing for agricultural purposes over here...

9/26/2003 7:18:14 AM

Caceres, mid west of Spain

There is not any agricultural gypsum in Spain either, but the normal cheap drywall gypsum available here is only Calcium sulphate, without fibber-glass, silicates (not bad anyway) or asphalt based wax emulsions. It doesn't affect the pH either and not any sulphur is needed to get that.
Maybe in the USA the normal gypsum can bring those things, and you need to go to a garden center to buy calcium sulphate (gypsum) to improve your soil, but here the only advantage in such a product is found in its easy way to spread, because as you said it is granulated.
What I do when adding drywall gypsum (the cheapest I can find is the one I purchase) is to spread it over dry soil and tillage it immediately.

Hope it helps, at least to the European growers.........Carlos

9/26/2003 9:44:14 AM

Cologne / Germany

Gypsum was used as a pure fertilizer around 1850. Later on it was used as a binding agent for the fertilizer industry since they found out it performs much better that way. This might be the reason you won´t find it as "agricultural gypsum" over here - it´s already contained in many other fert. products.
Don´t use home depot gypsum, I doubt it´s pure natural origin, maybe enriched with chemicals for construction needs. And Steve is right - it will definetely lower your PH, so what for as long as your soil is not acidic?

9/26/2003 10:28:01 AM

Cologne / Germany

P.S. in Germany they use it to "cure" acidic soil in the forests, along with lime. Anyone needs that in the patch;-)?

9/26/2003 10:32:58 AM

Ontario, Canada.

Searched all day for local suppiers of ag. gypsum. No luck.
Dwaine & Don are correct about calcium sulphate. I just can't find it. Nice article Tremor came up with.

9/26/2003 8:16:59 PM

Oz

gypsumsales.com,,,,,,,,,

9/26/2003 8:59:22 PM

Ontario, Canada.

Found Calcium sulpfate today at another area Co-op I had not called. It is in bulk though, not bagged. How much to apply with PH of 6.5

10/8/2003 9:36:11 PM

Ctpumpkin@optonline.net

That's what you're after!

pH won't be altered in your case & that's fine since 6.5 is OK. There are many other benefits to using it though. Added Calcium & Sulfur, both of which are good. Helps break up clay. Aids in water utilization/efficiancy. Leaches salts. Improves sodic soils.

I've used rates of 100-200 lbs per 1000 sq ft depending on soil test results, crop, goals, etc.

Check this website out. You might find it interesting. A little flashy with their claims, but OK none the less.

http://www.awgypsum.com/gypsum.htm

10/8/2003 11:44:05 PM

Ontario, Canada.

Tremor - Thanks for your help. I've picked a few lines from the link you posted. Calcium is nearly always only marginally sufficient and often deficient in developing fruits. Good fruit quality requires an adequate amount of calcium. Calcium moves very slowly, if at all, from one plant part to another and fruits at the end of the transport system get too little. Gypsum helps prevent blossom-end rot of watermelon.

10/9/2003 8:11:48 AM

Mill Bay, British Columbia

Steve, thanks for posting the link at http://www.awgypsum.com/gypsum.htm as it provides all the details you need regarding gypsum (calcium sulphate).

Glenn

10/9/2003 12:53:42 PM