Abstract <p>The substrate used for mass rearing of insect predators is of particular importance as it helps to avoid excessive contacts and reduces cannibalism. The aim of the present study was to evaluate the suitability of wheat seedlings as a substrate for rearing of nymphs of the predatory bug <i>Orius laevigatus.</i> The experiments showed that the use of wheat seedlings for nymphal rearing resulted in a substantial (about one and a half times) increase in the total number of emerged adults in comparison with the commonly used inorganic substrate, tulle fabric. Moreover, the weight of emerged males was also somewhat higher when they were reared using wheat seedlings, as compared with tulle fabric, whereas the differences in female’s weight and fecundity were not statistically significant. These results suggest that the use of cheap and easily grown wheat seedlings would increase the cost-effectiveness of <i>O. laevigatus</i> production for biological control in greenhouses.</p>