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Captain Cubensis
Bleeding HeartLiberal


Registered: 09/18/07
Posts: 648
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Gypsum, good or bad?
#7618803 - 11/10/07 01:28 PM (16 years, 2 months ago) |
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When preparing a casing layer its important to add to correct buffers to maintain a healthy pH level. For example, unlike hydrated lime, Agaricus mushrooms should not contain gypsum, as it drives the pH down in interaction with metabolites of the mycelium. This will lower the ultimate yield of mushrooms. Calcium Carbonate is the preferred source of calcium in casing, as it buffers the pH upward.
Does this apply to Cubes, or only Agaricus strains?
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RogerRabbit
Bans for Pleasure



Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 11 months, 3 days
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That makes no sense. In addition, every commercial agaricus farm I know of uses gypsum in their substrates. Gypsum is not used to change pH. That's the job of lime to raise pH or sulfur to lower it.
Gypsum contains both calcium carbonate and sulfur, thus it tends to keep the pH near neutral, preventing swings as the metabolites try to push the pH down. We add lime to make the casing layer inhospitable to competitor fungi which are less tolerant of a high pH than established mushroom mycelium. Calcium carbonate or hydrated lime is not used to counter the effect of the metabolites. As said above, that's what the gypsum does.
Use gypsum on substrates such as compost or horse manure, but don't use lime. Save the lime for the casing mix, where you should use gypsum and lime together. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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VisionsToReality
RIBBONS


Registered: 09/22/07
Posts: 1,083
Last seen: 16 years, 1 month
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Re: Gypsum, good or bad? [Re: RogerRabbit]
#7620080 - 11/10/07 07:26 PM (16 years, 2 months ago) |
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I thought the main reason why gypsum was used was so substrates do not aggregate, making it easier for mycelium to penetrate
-------------------- Life is one big road with lots of signs, So when you're ridin' through the ruts, Don't you complicate your mind. Flee from hate, mischief and jealousy Don't bury your thoughts, Put your vision to reality, yeah!
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RogerRabbit
Bans for Pleasure



Registered: 03/26/03
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Loc: Seattle
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That's why we add it to grains. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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VisionsToReality
RIBBONS


Registered: 09/22/07
Posts: 1,083
Last seen: 16 years, 1 month
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Re: Gypsum, good or bad? [Re: RogerRabbit]
#7620123 - 11/10/07 07:48 PM (16 years, 2 months ago) |
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Really...as in, WBS in jars? Didn't know that.
Although for other substrates it seems beneficial to have it not aggregate, either. But I guess the primary reason is because gypsum is acting as a buffer?
-------------------- Life is one big road with lots of signs, So when you're ridin' through the ruts, Don't you complicate your mind. Flee from hate, mischief and jealousy Don't bury your thoughts, Put your vision to reality, yeah!
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RogerRabbit
Bans for Pleasure



Registered: 03/26/03
Posts: 42,214
Loc: Seattle
Last seen: 11 months, 3 days
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It's more of a stabilizer. Gypsum helps to prevent swings in either direction. The ability to prevent clumping is why we use a small amount in grain jars. I'm sure it's a side benefit in substrates and casings as well. The other benefit of gypsum is to supply calcium and sulfur, which are both essential for good fruit body formation. Some substrates seem to have enough of both to develop great fruits without it, but it's still there for the pH stability. I pay just over $3 for a 25 pound bag which goes a long way, so there's no reason not to use it. RR
-------------------- Download Let's Grow Mushrooms semper in excretia sumus solim profundum variat "I've never had a failed experiment. I've only discovered 10,000 methods which do not work." Thomas Edison
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BUDDHA_702
Master Mycologist In Training



Registered: 02/17/07
Posts: 1,296
Loc: Some Country
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Re: Gypsum, good or bad? [Re: RogerRabbit]
#7620144 - 11/10/07 07:56 PM (16 years, 2 months ago) |
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Were do you get hydrated lime? I checked lowes and they had none.
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VisionsToReality
RIBBONS


Registered: 09/22/07
Posts: 1,083
Last seen: 16 years, 1 month
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Re: Gypsum, good or bad? [Re: RogerRabbit]
#7620151 - 11/10/07 07:58 PM (16 years, 2 months ago) |
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Thanks for the info RR. 1 more - I've read its best to use gypsum dry on dry substrates so it mixes evenly.
What about mixing a gypsum solution in water, first, then using that solution to mix into the already moist substrate? That'd be fine, right?
-------------------- Life is one big road with lots of signs, So when you're ridin' through the ruts, Don't you complicate your mind. Flee from hate, mischief and jealousy Don't bury your thoughts, Put your vision to reality, yeah!
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Captain Cubensis
Bleeding HeartLiberal


Registered: 09/18/07
Posts: 648
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Re: Gypsum, good or bad? [Re: RogerRabbit]
#7625833 - 11/12/07 01:56 PM (16 years, 2 months ago) |
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Quote:
RogerRabbit said: That makes no sense. In addition, every commercial agaricus farm I know of uses gypsum in their substrates. Gypsum is not used to change pH. That's the job of lime to raise pH or sulfur to lower it.
Gypsum contains both calcium carbonate and sulfur, thus it tends to keep the pH near neutral, preventing swings as the metabolites try to push the pH down. We add lime to make the casing layer inhospitable to competitor fungi which are less tolerant of a high pH than established mushroom mycelium. Calcium carbonate or hydrated lime is not used to counter the effect of the metabolites. As said above, that's what the gypsum does.
Use gypsum on substrates such as compost or horse manure, but don't use lime. Save the lime for the casing mix, where you should use gypsum and lime together. RR
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Captain Cubensis
Bleeding HeartLiberal


Registered: 09/18/07
Posts: 648
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I got that info from mycosupply, a Shroomery sponsor.
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Alphanautics
Goonmaster



Registered: 11/26/07
Posts: 103
Last seen: 4 years, 25 days
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Re: Gypsum, good or bad? [Re: RogerRabbit]
#7713320 - 12/03/07 10:29 PM (16 years, 1 month ago) |
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good information here.. thanks RR. I was kind of wondering about different supplements I could add to my oat straw during casing.. gypsum will be for sure. I read that stamets digs grass meal (although used when cultivating a different species) and claims that it adds to the yield and potency. Any other ideas for supplements? Just straw and gypsum doesn't seem all that nourishing.. but maybe we don't want to overdo it for the sake of minimizing contams..
let me know what you think/ have tried. i'm trying to prepare as best i can for my first bulk casing.. wish me luck
-------------------- Word em up
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