Effect of biostimulators on growth of vegetables in hydroponical systems

Biostimulators could be used to stabilize hydroponical systems and to counteract stress situations. The experiment aimed to investigate the effect of lactic acid (LACTOFOL O), K-Humate and Bacillus subtilis as biostimulators in substrate culture of Cucumis sativus cv. Jessica. All substances were applied separately or in combination on leaves and roots respectively, in total 8 different treatments have been compared with the control. For each treatment 20 ml of 0.08% LACTOFOL 0, 0.2% K-Humate or 10(7) cfu/ml spore suspension of Bacillus subtilis were applied three times in weekly intervals during the 5 till 10 leaf stage. Biomass of shoots and leaves was enhanced due to the application of these substances. Also the dry matter content was higher in treated plants than in the control. After application of each biostimulator investigated to the roots the number of marketable cucumbers was enhanced in total and in relation to the non-marketable fruits. The application of K-Humate enhanced also the dry matter content of the cucumbers. The application in the root zone had a stronger effect than the application on the leaves and should be preferred. The combined application of all substances was possible but should be investigated further.