Horticulture needs large amounts of substrates, the most important being the natural peat, coconut fibre and rockwool. In Switzerland peatlands are protected since 1980. Nevertheless, 150’000 tons of peat are imported each year. The current demand for the Swiss market is to develop substrates without peat by presenting the same quality as of peat-based substrates. In particular, the water retention properties of substrates without peat is a critical physical factor allowing an optimal development of the plant. Within this framework, the aim of the present study was to perform a comparison of different substrate compositions, an analyse of their physical properties with focusing on desorption properties and a comparison of their performance for two ornamental crops: pelargonium and schefflera. Firstly, the physical properties of water retention of the substrates were carried out using a desorption table. This table allows to apply different suction forces to simulate the behaviour of the substrate when the plant roots absorb the water. With this desorption test, the following parameters were measured: the total porosity, the aeration at pF1 and the amount of available water for the plant. Secondly, plants were grown during 4 months in 6 different substrates tested, with or without peat. Plants were grown in containers and irrigated with drip system. Electro-conductivity (EC), plant growth, the production of flowers were followed every week. Above-ground plant weights were evaluated at the end of the trial. In the light of the pelargonium and schefflera crops, it appeared that no-peat substrates tested in this study allowed a similar plant growth than peat substrates. In addition, the water retention properties of these substrates were close to the ones measured on peat based substrates. A difference in average value of EC appeared between the no-peat and peat substrates. To conclude, the performance of no-peat substrates were similar to with-peat substrate ones. However, due to EC differences, the fertilization of no-peat substrates have to be adapted to optimize the growing conditions.