The amount of peat moss needed to amend 240 square feet of soil depends on the depth desired. For example, 20 cubic feet of peat moss is necessary to create a layer that is 2 inches deep, according to the Canadian Sphagnum Peat Moss Association. 10 cubic feet would create a layer 1 inch deep.
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Marie Notnats enjoys learning about new topics and teaching people new skills. She has been writing professionally since 2008. She is a professional horticulturist with a Bachelor of Science degree in horticulture from Brigham Young University. She writes for About.com, Examiner.com, eHow, and assorted gardening blogs.