cellulose fiber of the present invention 2 fill each testing sample of the natural sphagnum moss and the artificial peat moss produced from natural cellulose fiber of the present invention into respective measuring soft pot in flush full manner so that each testing sample volume vm is the same as containing volume vp of the measuring soft pot namely vm vp 3 slowly add water into each testing sample in respective measuring soft pot up to saturation manner but without spillage due to overfilling or sample floating out of each measuring soft pot 4 keep each measuring soft pot still for 15 minutes to allow each testing sample for completely absorb added water in lower down manner of the water level then slowly add water again into each testing sample in respective measuring soft pot up to saturation manner 5 measure and record overall quantity of adding water to each testing sample in respective measuring soft pot for denoting as wadd respectively 6 tear off the adhesive tape sealed each drainage bore in the bottom of respective measuring soft pot to allow water therein naturally draining out for about an hour then collect each drained water from each measuring soft pot of respective testing sample for denoting.