Lime and gypsum supply calcium. Since magnesium often occurs with limestone, it ends up in agricultural lime, further enriching soil. Sulfur sometimes occurs with gypsum, adding extra soil nutrition.

Read more: Gypsum Vs. Lime for Soil : eHow.com http://www.ehow.com/facts_5846214_gypsum-vs_-lime-soil.html#ixzz1pEs7Ai5J

Ligna peat is ground up redwood bark sometimes used as a substitute for peat.

Thanks lgteacher!

Hi w2,
Please also note that lime is used for the 5-1-1, not gypsum. Although both are calcium sources, only lime will adjust the inherantly low ph of the 5-1-1 to an acceptable level. Gypsum is utilize for composing the gritty mix.

Additionally, I don't know anything about Ligna Peat, however, if you are looking for an alternative to peat, simply use the portion of pine bark dust that passes through your 1/16" mesh (insect screen).

PJ

Use Gypsum and epsom salts in 5-1-1 instead of dolomitic lime only when you want the pH to stay low such as for acid loving plants such as rhododendrons, blueberries, azalea's etc. and plan to use fertilizers commonly low in Ca and Mg such as MG 24-8-16 and others.