The ridge drying method of sod peat (the Tupla method) was developed in Optimiturve research program during 1988-1990. The increase of seasonal yield using the Tupla method in comparison with Palahaku method was over 70 %. The dry matter loss decreased 10-20 % from the level of losses of traditional methods, which is 30-50 % The production costs decreased by about 10 %. The best seasonal yields were obtained by 55 mm sod. The yield of the tupla method of the production studies made in the Northern Ostrobothnia were 820 MWh/ha in 1989 and 670 MWh/ha in 1990. In addition to the method development, the project also contained equipment development. The equipment dealing with surface sod cutting, the sieving of the ridges and the stockpile sieving were the targets of the research.