Mixing Hydrogel Granules into Peat Substrate Improves Germination and Enhances Growth and Physiological Performance of Tomato Seedlings

Abstract The effects of hydrogel granules mixed with peat substrate on germination, morphological and physiological parameters of plugged seedlings were tested in tomato seedlings, at two different irrigation regimes. Due to hydrogel presence, the germination speed was increased, whereas mean germination time was significantly reduced. Slight improvement was recorded regarding final germination, but no effect was found regarding the synchronisation index and seedling vigour index. Due to addition of hydrogel granules a significant increase occurred in dry matter of shoots and plants. No effect was found regarding dry matter of roots, but the presence of hydrogel granules significantly reduced the length of tap root. Interestingly, stomata conductance and chlorophyll index were higher than in control plants. No statistically significant interaction was found between hydrogel variants and irrigation frequency, i.e., the effect of different levels of hydrogel variants did not depend on irrigation frequency. Therefore, we recommend mixing hydrogel capsules into the substrate of plug seedlings to improve the morphological and physiological parameters of seedlings and reduce water and fertiliser leaching into the environment.