Natural fibres such as hemp are extensively used in new composite materials. This article deals with biological and mechanical aspects of hemp phloem fibres. The effects of different cultural parameters on some characteristics of hemp fibres were studied: variety, soil drought during plant cultivation and water-retting process. Results showed that there was no significant influence on studied properties of the hemp variety and of water-retting. Under water-limited conditions, results showed that plant growth was reduced and the maturation of phloem fibres was delayed. Secondary cell wall was synthesised later in comparison with water-controlled conditions and cell protoplast remains longer. These biological aspects can be related to the higher Young’s modulus and maximal stress values measured on fibre strands from plants grown under water-stressed conditions. These results are promising, by considering the extent and degree of drought conditions in the world.