40 replies to this topic

[chill]

Hi,

Can calcium carbonate be substituted one for one with hydrated lime or does it require a different recipe?

Oh, can anyone tell me where to get pickling lime? No one on in my city has heard of it. I checked feedstores, wally world, craft stores, canadian tire (hardware store), garden shops, you name it.

[bluehelix]

Hydrated lime should not be used. Calcium carbonate should be used to balance out peat moss. The only people using hydrated lime are hobbyists, and depending on the grade and exactly how much one uses, it could be a total disaster. Some grades of hydrated lime are extremely caustic and strong.

No mushroom farm in existence would use hydrated lime. In fact I challenge anyone to find me a single mycological text referring to it for casing pH balancing. There are numerous reasons why to not use it for this purpose. First, it has a pH of about 12.5 which means it can very easily create way too basic of a casing, burning the mycelium and killing it. With peat varying so much in its pH, there is no sensible way to use calcium hydroxide (hydrated lime) because one doesn’t know how much to add unless one has a very good pH probe, which cost about $100 to $150. Secondly, hydrated lime converts to calcium carbonate, a weaker base, upon a reaction with the air. This can take days or weeks depending on the amount of exposure and how much water is present. In the case of a casing, it would likely be about a week. After all the hydrated lime converts to calcium carbonate, the pH will fall. In the later flushes, the pH would continue to fall unless calcium carbonate chips of some sort were used. Calcium carbonate doesn’t lose its buffering ability so easily like that.

If one intends to use hydrated lime, it must be used (a) with a sensitive pH probe to monitor the casing since peat varies in pH a lot and the mix can easily become too basic, and (b) with the aid of some chip or powder form of calcium carbonate which can hold the pH up in the long run. I don't use hydrated lime at all. It's not used by the pros, and I see no benefit over using regular calcium carbonate which is the gentle buffer that is normally used.

Calcium carbonate powder can be purchased in the many forms. You can find it in a reasonably pure form at some garden stores sold as “garden lime” in the form of ground oyster shells, but read the label: you are looking for ground oyster shells, limestone, or any other form of calcium-carbonate-based lime, not dolomite-base lime (which is a magnesium-rich form). Another place to find pure calcium carbonate is from wine making shops. Call some home brewer shops and ask for calcium carbonate powder; they’ll know what you want. Another method to derive it from hydrated lime is to spread your hydrated lime no more than about ½ inch thick on the bottom of 13"x8" glass pan (do NOT use a metal pan), and cook at 350F for about an hour. The heat and CO2 in the air will covert most if not all of the hydrated lime to calcium carbonate.

[bluehelix]

chill, calcium carbonate and hydrated lime are totally different beasts. You certainly cannot use one for the other. It takes about 1.2 cups of garden-lime grade of calcium carbonate to balance out 15 cups of loosely-packed peat moss to a pH of around 7.5. If you end up using the very pure form of calcium carbonate used in wine making, use only 1 cup per 15 cups of peat moss since it's more reactive in my experience.

Calcium hydroxide (hydrated lime) varies in quality so much that one cannot really give very good recommendations of how much to use. The reason is because some forms have a lot more calcium carbonate in them than others. It's strength really depends on how the powder was protected from moisture and fresh air during storage.

[chill]

Hi Bluehelix,

thanks for that. Very helpful.

I did a little research and sources of calcium carbonate include tums and rolaids.

Good source, bad source? There is a wine store near me. I'll give them a call.

Your ratio of 1:15 for peat moss wouldn't apply directly to cactus mix which is only partially peat moss, the rest being made up of sand etc. I'm thinking that I'd use say 1/2 as much CC. Correct?

So:

Say I want two cups of cactus mix for the casing (500 ml) I would want 17 ml of calcium carbonate and 10ml of gypsum?

[chill]

Well I just called my local beer brewing store and they are willing to sell me BOTH calcium carbonate and gypsum.

This seems like a good tip for people in my situation (ie: not wanting to use 50 lbs of hydrated lime) who are having trouble finding supplies.

[waylitjim]

Hydrated lime should not be used. Calcium carbonate should be used to balance out peat moss. The only people using hydrated lime are hobbyists. If one intends to use hydrated lime, it must be used with a sensitive pH probe to monitor the casing since peat varies in pH a lot.

I've used hydrated lime for almost every grow I've ever done, and with much success. I use it in my casing mixtures and for bulk substrate soaks. I've never had negative results from using it and I don't use a pH probe. I'm not dumping the lime directly on the casings, it always gets diluted during the pasteurization process. And yes, I am a hobbyist. :)

[anticheffy]

yea me too
hydrated lime is almost solely recomended in everything Ive read
I use it exclusivly and have NO failures

Im a hobbyist to though

[bluehelix]

Cactus mix is already pH-balanced with calcium carbonate to around 7.0. You don't need to add any more.

I am glad that some have luck with hydrated lime. The form I tried was very pure and so strong that it totally wiped out my entire bed almost overnight. The strong stuff is snow white and burns your nose. The weak stuff at garden stores is a mix of that and regular calcium carbonate.

Just because you found some super weak agricultural grade doesn't mean that is what everyone will find. Pickling lime, one of the most typical forms of hydrated lime, for example will not work well. I don't care how many grows you did with your weak garden lime, the fact is that others may find much stronger lime that hasn't reacted with the air for so long. Calcium carbonate, on the other hand, is much more consistent. You only have to deal with particle size, not how reacted it is with the air because it's stable.

As for using tums or rolaids, that too is a bad idea. Those are usually packed with all sorts of other things, sometimes including sugar and magnesium. Get normal garden lime derived from calcium carbonate sources or a pure form used in wine making.

[bassplar99]

Getting a lot of different info here. I have to ask, if you do not use gardening, agricultural, or gardening lime, what else is there? What brands does everyone use? And Rodger, I am curious since I follow your straw teks but would like to start using a steamer, how would you suggest incorporating lime into the pastuerization process? I was thinking a soak in warm water with lime for a period and them steam and hang to dry to the proper moisture. I would like feedback from anyone though, very interested in this.

[bluehelix]

Oh, and by the way, you can't really add too much calcium carbonate because it stops reacting much after you get a pH of around 8.0 to 8.4. Hydrated lime, on the other hand, stops reacting around 12.5, strong enough to eat the tissues out of your nose so don't breath the dust unless you want a really clean nose.

[bluehelix]

waylitjim, the process you describe, soaking and then pasteurizing, probably converts the vast majority of the hydrated lime to calcium carbonate. Heat and exposure to carbon dioxide quickly convert all the lime to calcium carbonate given a weak solution to begin with. There is a technique to pasteurize straw using calcium hydroxide where one makes a warm to hot bath of saturated calcium hydroxide (1 teaspoon per gallon is all that is needed for saturation), soaks the straw for a bit, and then lays it out to drain and dry. This technique is covered in detail in "Growing Gourmet and Medicinal Mushrooms" among others.

[bluehelix]

bassplar99, the strongest grade of lime I know of is food-grade (CODEX) hydrated lime. This is an extremely pure grade with and ultra find particle size (like flour) that is used for cooking. It's stored in water/air resistant bags. For example, it is used in the making of tortillas to boost pH to prevent premature molding. If you use that grade, you'll need to be very careful. Anything even remotely close to 1.2 cups per 15 cups of peat is way, way too much. It'd be closer to a teaspoon per 15 cups of peat, but don't quote me on the numbers. A soak in a saturated solution probably would work (as Waylitjim said), but if you are using cactus mix, you don't need to pH balance it because they've already done that for you! Just throw in some oyster chips or aragonite sand and you're good to go for a perfect mix.

[waylitjim]

The form I tried was very pure and so strong that it totally wiped out my entire bed almost overnight. Just because you found some super weak agricultural grade doesn't mean that is what everyone will find.

Alot of respectable growers around here have used hydrated lime with much success. Just because you had bad luck with hydrated lime, doesn't mean everyone else will. Although most people have great success from using horticultural hydrated lime, some do not. Blue, I respect you as a grower, and I know you're a good person too. :) But I don't want people to get the wrong idea about hydrated lime. It works well, and professionals use it too as RR mentioned above, it's what stamets recommends .

Pickling lime, one of the most typical forms of hydrated lime, for example will not work well.

Pickling lime is food grade calcium hydroxide (hydrated lime) with no additives or preservatives. Be careful with what you say, what works for some will not work for others and vice versa.

I'm not saying Calcium carbonate doesn't work well. But many brands of picking lime and hydrated lime work equally well. You can disagree, but it's been proven by various people here. The reaction of hydrated lime with CO2 gas = calcium carbonate, there's very little difference between the two. You do have to be careful with the kind of lime used, you never want to use dolomitic hydrated lime, always use high calcium horticultural hydrated lime with Mg. levels below 5%

Chill...sorry to derail your thread. :)

[bassplar99]

I shoudl clairfy also, I am only steam pastuerizing straw, not casing materials. Sorry got a little off topic but the discusion of lime was going on. I remember pickling lime for $2.99 being posted on here at one point as a good source of lime.

[bluehelix]

In casing mixes, hydrated lime gives an immediate ph correction, and it lasts as long as the average casing lasts. I use one teaspoon of hydrated lime per cup of peat in my 50/50 casing mixes, along with a tablespoon of gypsum per cup of peat. The gypsum, which contains both calcium and sulphur, helps to moderate the hydrated lime. I have never, and I repeat never had problems with using hydrated lime. It is what I recommend over calcium carbonate due to it's very fast acting properties. If one can't find hydrated lime, then use pickling lime/calcium carbonate. But, in my opinion, it's a second choice, not the first.

Ok, we must be talking about totally different types of hydrated lime here. What EXACTLY are you and Stamets using? If it's so advanced, why is it not mentioned in his texts? One teaspoon of what I have per cup would drive the pH to 10+ for days if not weeks, surely killing everything eventually. You say hydrated lime? I have 98.5% pure calcium hydroxide (aka hydrated lime). It's called CODEX Hydrated Lime and is manufacturered by the Mississippi Lime Company. Here is a specifications sheet:

http://www.mississip...04&tabsetting=2

Now, I know exactly what I was using, and I know for a fact that you cannot use a teaspoon per cup. Now what where you and Stamets using? Do you want me to do an experiment to tell you how many weeks the casing pH remains above 9.0 using a teaspoon per cup of the hydrated lime I have? I am willing to do it. My guess would be at least a month before enough was converted to calcium carbonate to bring the pH back down to 9.0.

I am not saying it can't be used. I HAVE used it, but I was really careful with it. I also found the pH holding ability to totally suck compared to calcium carbonate. If you are shooting for one or two flushes, though, it probably doesn't matter.

PS - Oh and pickeling lime is hydrated lime. It's very close to pure hydrated lime too (over 98%).

[bluehelix]

Ok. I am doing the experiment now. I'll let you guys know how it turns out. I am adding one teaspoon of calcium hydroxide (hydrated lime) per a cup of sphagnum peat moss. I'll let you know how it goes.

Ok. I just did mix it up really well. The initial pH of the 1 teaspoon hydrated lime to 1 cup peat is 12.4 using a recently calibrated pH probe that is accurate to +/- .1

I will post each day updating you here. It's exposed to the air too so the pH should fall slowly.

[waylitjim]

That doesn't look like the type of hydrated lime recommended for growing mushies. You want Horticultural Hydrated Lime, not dolomitic or other kinds, otherwise like you say, it'll burn the mycelium and mushrooms wont grow. Hi Yield brand is a good one.

[bluehelix]

Here is the data sheet for it:

http://www.gardnwise...d Lime Hi Yield'

Looks like pure calcium hydroxide to me. I wish I could get my hands on it. If anyone knows where to buy it, let me know. I'd like to examine this stuff for myself.