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Hey guys,
Can you tell what the formulas are for the two different limes we have to use? Just to make sure,
Hydrated Lime (Calcium hydroxide) Is it Ca(OH)<sub>2 </sub>?
and Agricultural Lime (Calcium carbonate) <b>Is it CaCO<sub>3</sub></b>?
Regards!
Karla asked:
Hey guys,
Can you tell what the formulas are for the two different limes we have to use? Just to make sure,
Hydrated Lime (Calcium hydroxide) Is it Ca(OH) ?
and Agricultural Lime (Calcium carbonate) Is it CaCO?
Regards!
In my country, I’ve found different kind of hydrate lime, and I cannot decide wich buy.
Can you tell?
Hi Karla,
Yeah, sure, the two different types of Lime are:
You would use the Calcium Carbonate mixed in with the coffee grounds to act as a buffer and keep the substrate pH higher during growth, and you use the Calcium Hydroxide for pasteurising straw.
Best wishes,
Adam
With the Hydrated Lime, the main thing is that it is high Calcium content, and low Magnesium content.
Ideally Calcium content is around 95% or more. High Magnesium content (anything over 10%) is not advisable as it will stunt mushroom growth.
Hydrated lime made from Calcium Carbonate is the one you want, and any made from Dolomite Lime will tend to have the high Magnesium content.
Hope this helps,
Adam
Thanks a lot.
Just wondering, would baking soda (sodium hydrogen carbonate) be a good alternative to agricultural lime?
Hi Jon,
I don’t know about baking soda to be honest – never tried it. Let us know how you get on if you give it a try.
Best wishes,
Adam
Chalk is also calcium carbonate. Can you use powdered chalk in the same way as lime? Presumably there is a structural difference between the two that may affect the way it is absorbed. Has anyone tried it?
I live on very chalky soil and have a ready supply of great lumps of it lying on every ploughed field. Would it need to be baked (pasteurised) before using it? It tends not to pick up mould or organic matter in the ground but might still harbour dormant spores?
I’ve added egg shells to my mix. I bake the eggshells in a 250 (f) oven to destroy any pathogens. Then I grind them very fine with a spice grinder and mix them with the coffee.
Hi John, yes indeed – the stuff usually bought as calcium carbonate is just finely ground chalk, so you could use the stuff you have access to if you were able to grind it up and then pasteurise it in the oven for half an hour.
I love your use of egg shells Maureen! Great idea 🙂
It’s worth noting, that in recent trials we’ve been running with and without the additional of agricultual lime to the substrate – we have found no clear benefit to adding it. We are due to update the course material soon to reflect this, but in the meantime it might save you the effort of grinding the chalk up John and you could just go ahead and make your bags up without it 🙂
Adam
In Australia we only seem to have 2 types o lime- garden dolomite lime and builders lime- I cant see on either packets the calcium or magnesium content.
Hi Jennifer, in Australia I think this is what you would use – can anyone confirm? If it is you can pick it up at Bunnings.
http://www.richgro.com.au/products/fertilisers/garden-lime-2-5kg/
http://www.richgro.com.au/wp-content/uploads/2014/02/Richgro-Garden-Lime-MSDS.pdf
I was also wondering about this one though http://ecoorganicgarden.com.au/products/soil-improvers/eco-flo-lime/
Hi Leisha, the links you have there are all for garden lime (Calcium Carbonate, CaCO3) which is no longer neccessary to add to the growing mix. In recent experiments we’ve found that adding agricultural lime (as mentioend in module 3 at present) to the coffee/straw mix is uneccessary, and that you can have perfectly good results without it. We are due to update the course information in the weeks ahead, and the recipe we will recommend to people will simply be:
for every 1kg of fresh coffee grounds, add:
150g pasteurised straw (either lime bath or hot water pasteurised)
150g oyster mushroom spawn
The lime needed for the lime bath pasteurisation is Hydrated Lime – which is sometimes also called Builders Lime. It usually has less than 10% magnesium content (which is good), but worth checking this with the supplier if possible.
Hope this helps a bit – all the different types of Lime out there does make it pretty confusing!
Hi guys,
What concentration of lime do you use in your lime baths?
Jon