Reference number of the aid programme: SA.42799(2015/X), help_de_minimis: §42 of the Regulation of the Minister of Infrastructure and Development of 10 July 2015 on granting financial assistance by the Polish Agency for Enterprise Development within the Operational Programme Intelligent Development 2014-2020.The subject of the contract is a research and development service consisting of developing assumptions, algorithms and making prototypes of sensors measuring humidity, electrical conductivity and gardening substrate temperature. In the assumption, the sensor is to measure the values of relative permeability and electrical conductivity of the corresponding parasite system of the lost capacitor of the measurement probe. This sensor will be used in precision agriculture for crops conducted on soilless substrates. These are gardening substrates with low inertia and high water capacity such as mineral wool, glass wool, peat, coconut fibres, perlite, vermiculite and others, are widely used in horticulture production, min. in flower and vegetable distribution, container nurseries of ornamental plants, pot plants and herbs, and “soilless” cultivation of vegetables and berries. These substrates are characterised by: — high water capacity with relatively higher air content, – zero or limited minerals (mineral components are supplied primarily in the form of slow and/or controlled fertilisers and by the irrigation system – fertigation). Salinity of gardening substrates depends on the requirements of cultivated plants. In practice, it may vary from very low values (e.g.: orchids) up to relatively high (over 4mS/cm for tomatoes). The measuring probe shall have the appropriate dimensions and design to ensure easy installation in the ground: it must be characterised by a small cross-section: hence, it should have a rod or other form that ensures good contact with