From the study of experimental materials from plants that are used are rice Husk, copra meal, wood dust, corn silk and orange Peel. All five types of materials by each 100 grams on the ground from clay storage method and mix with the soil already left two weeks by measuring the pH of the soil every five days apart, measure soil pH and comparison soil pH between rice Husk, copra meal, wood dust, corn silk and orange Peel. It appears that rice husk can lower the pH the best. The materials from plants that can best compare is a measurement of the amount of 150 grams of rice husk by 200 g and 250 g measured soil pH of 5 days each time. It appears that the quantity of 200 grams of rice husk can lower the pH value as part of its planted hevea brasiliensis.