RogerRabbit said:

If you lived in a high trich spore load area, you wouldn't consider the few minutes it takes to drive to a feed store, nor the six bucks for a lifetime supply of hydrated lime a waste.  Don't make the mistake of thinking in a few months of growing you've learned all there is to learn.  Wait until you've had a big trich outbreak and then every project takes a dive.  You'll be screaming for some lime.

Gypsum has been proved by commercial farms for many years to provide up to a 25% to 35% boost in yields over not using it.  If you don't have your substrates tweaked in yet, don't knock gypsum.  Once you get the best possible substrate mix, gypsum will add considerably to yields.  That's a fact.
RR

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Q. What is lime? What are the differences between quicklime and hydrated lime, high calcium lime and dolomitic lime?

A:  Lime is a generic term, but by strict definition it embraces only the manufactured forms of lime—quicklime and hydrated lime. It does not include limestone, which is the feedstock for lime manufacturing (click here for a short description on how lime is produced).

Quicklime, the product of calcination of limestone, consists of the oxides of calcium and magnesium, and in the United States it is available in three forms:

High calcium quicklime--derived from limestone containing 0 to 5 percent magnesium carbonate.  

Magnesian quicklime--derived from limestone containing 5 to 35 percent magnesium carbonate.

Dolomitic quicklime--derived from limestone containing 35 to 46 percent magnesium carbonate.

Hydrated lime is a dry powder manufactured by treating quicklime with sufficient water to satisfy its chemical affinity for water, thereby converting the oxides to hydroxides. Depending upon the type of quicklime used and the hydrating conditions employed, the amount of water in chemical combination varies, as follows:

High calcium hydrated lime--high calcium quicklime produces a hydrated lime containing generally 72 to 74 percent calcium oxide and 23 to 24 percent chemically combined water.  

Dolomitic hydrated lime (normal)--under atmospheric hydrating conditions only the calcium oxide fraction of dolomitic quicklime hydrates, producing a hydrated lime of the following chemical composition: 46 to 48 percent calcium oxide, 33 to 34 percent magnesium oxide, and 15 to 17 percent chemically combined water.

Dolomitic hydrated lime (pressure)--this lime is produced from dolomitic quicklime under pressure, which results in hydrating all of the magnesium oxide as well as all of the calcium oxide, producing the following chemical composition: 40 to 42 percent calcium oxide, 29 to 30 percent magnesium oxide, and 25 to 27 percent chemically combined water.

agar said:

http://cgi.ebay.com/Horticultural-Hydrated-Lime-2-bag-Ca-OH-2_W0QQitemZ180028876837QQihZ008QQcategoryZ20540QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

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Grazie!!

agar said:

I hear ya there.
Same for oyster shell flour.
I pay $7 for 50 lbs.
most pay that much for a 3 lb box.

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