Whats difference between pulverized and dehydrated lime?

Are they both the same thing but one is processed differently? I see gardeners at the community garden use lime. They said it keeps the insects and animals eating there plants. Is there any truth behind this?
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I mean

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Lime is CaO (Calcium Oxide) and it is hygroscopic-i.e., water absorbing. Unless one used lime right from a kiln, lime picks up around 1% H2O. Now if you mix lime with water, you get calcium hydroxide Ca (OH)2. In most tropical countries, this hydrated lime is pained on walls. Yes- it kills most bacteria. All pulverized lime is hydrated unless you store in Nitrogen atmosphere. The lime that is used in gardens is just lime (pulverized or otherwise) which has naturally picked up some moisture.

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The lime that is used on gardens mostly ie "garden lime" is Calcium Carbonate not Calcium Hydroxide. Hydrated or slaked lime or builders' lime, Calcium Hydroxide, may be used on gardens in some cases but it must be used differently. Both raise the pH (reduce acidity) but garden lime is slower acting and is less likely to raise the pH an excessive degree if applied heavily which can happen with hydrated lime. Both are used to amend the soil by raising the pH (so making other minerals available to plants) and/or to supply Calcium.
I cannot see how applying either lime to the soil could stop insects or animals from eating the plants. Applying hydrated lime to cover the plant as a dust might discourage those wanting to eat it but at the same time it will wash off easily and then start amending the soil pH which may be quite unwanted, especially if you are growing acid-loving plants. There are much better ways to keep the bugs off your plants.
I suggest that you talk to the more experienced gardeners at your community about what sort of lime they use, why and how much they use, before you do anything rash.
David
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"............. In most tropical countries, this hydrated lime is pained on walls. Yes- it kills most bacteria. ........"
This is known as "White wash" and has been used for several hundred years in Europe for painting dwellings and farm buildings. it is very good as a deterrent/killer for fleas and other similar insects.
--
David Hill
Abacus nurseries
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If they call lime stone as "lime" in the garden world- then lime stone cannot kill didly squat!

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