Climate variables such as temperature and precipitation are the major abiotic environmental factors determining the yields in crop plants. Given the observed trends in climate change, it is important to carry out analyses aimed at description and selection of plant species characterised by not only the best performance traits but also the best adaptation to climate changes. This study focused on phenological-morphological-biochemical investigations, comparing Allium sativum with A. ampeloprasum var. ampeloprasum GHG-L. We present analyses of economically important traits (biomass and allicin levels) in garlic and GHG-L grown in ecological system and effect of environment fluctuations on these traits. Comparative analysis of the biomass and allicin level in the underground part of garlic and GHG-L revealed not only substantial differences between the species and cultivars, but also great impact of the climate variables on these traits. It was found that garlic and GHG-L cultivated in adverse conditions, exhibited lower yielding rates, but the content of allicin was inversely proportional to the biomass. It should be emphasised that, irrespective of the climate fluctuations, GHG-L produced higher biomass and exhibited higher allicin level than garlic grown in the same conditions, indicating that GHG-L is well adapted to adverse climate changes.