## 1 Introduction  
_Stevia rebaudiana_ [PERSON] is a plant of the _Asteraceae_ family originating from Paraguay. Stevia produces an interesting array of biologically active compounds characterised by a very sweet taste. The plant-derived steviol glycosides present in stevia (over 30 have been identified) may be up to 300 times sweeter than sucrose [1]. At the same time, the stevia plant possesses a low energetic value at the level of 2.7 kcal g\({}^{-1}\) d.m. Stevia is also a source of important antioxidants, such as polyphenic metabolites, including flavons, flavonoids and chlorogenic acids. Due to these properties, the stevia plant is widely used in the food, pharmaceutical and cosmetic industries [1; 2]. As diabetes, caused mainly by sugar consumption, becomes a more crucial problem worldwide, more analyses of the viable sources of sugar substitutes seem like an adequate avenue of research in the fields of agriculture, biotechnology and food technology. Various in vitro and in vivo studies have revealed that steviol glycosides possess glucogonostatic, insulinotropic and antihyperglycemic properties [3]. Rebaudioside A and steviol can induce various anti-inflammatory, antidiarrhoeal, diuretic and immunomodulatory actions [4]. Furthermore, studies on rats revealed that the consumption of stevia leaves can decrease glycaemia and gluconeogenesis [5]. In a similar study performed by [PERSON] et al. (2019) [6], the consumption of stevioside had positive effects on blood glucose levels and lipid profiles as well as on advanced glycated end products. A study performed on humans, with a group consisting of lean and obese individuals, revealed that the consumption of stevia (compared with sucrose or aspartame) has shown positive effects, such as reduced postprandial glucose levels or postprandial insulin levels. Other authors [7] also describe the positive effects of stevia consumption on the postprandial glucose level. A study conducted by [PERSON] et al. (2013) [8] has shown that steviosides from stevia can improve 3T3-L1 insulin sensitivity by enhancing the expression of proteins that are involved in the insulin signalling pathway. Rebaudoside A, another stevioside, in the study by [PERSON] et al. (2012) [9], had an influence on reducing blood glucose levels in rats with diabetes and has exhibited protective action towards the pancreas. Stevia and steviosides also have anti-inflammatory and antimicrobial properties [10]. Research conducted by [PERSON] et al. (2018) [11] has shown that stevia leaves can be used to produce extracts that possess antimicrobial properties against _ Bacillus subtilis_, _Klebsiella pneumonia_, _Proteus vulgaris_, _Streptococcus pneumonia_, _Staphylococcus aureus_ and _Pseudomonas fluorescence_. These results and the fact that people have a growing interest in a healthy lifestyle and in having natural ingredients in food results in an increased demand for herbal raw materials and consequently leads to the more extensive cultivation of plants with functional and healthy properties, stevia included [12; 13; 14]. This plant is currently grown in a variety of countries besides South America, such as China, Malaysia, Singapore, South Korea, Taiwan and Thailand [15]. However, there is not much information about the viability of _Stevia reboundiana_ plantations in various countries characterised with a cooler climate than the native region of stevia. Due to the fact that stevia is currently used worldwide, stevia cultivation in the country in which stevia plants would be used in the production of various food products or cosmetics could possibly reduce costs and carbon emissions due to the reduction in the distances needed for stevia transportation [16; 17]. This study analysed the possibility of cultivating _Stevia reboundiana_ Bertoni plants in Poland and additionally aimed to determine whether varying plant spacing during stevia cultivation can influence various characteristics of stevia plantation, such as yield, growth parameters and the composition of the produced plants.