Our paper aims to assess the effect of Agroaquagel hydrogel on the changes of hydrophysical and biological properties of the unproductive chemically degraded soil and tailings. The experiment used two substrata: soil-loamy sand (P1) and tailings-sand (P2). The scheme of the experiment comprised five treatments: 0, 0.2%, 0.6%, 1%, and 2% doses of hydrogel. Hydrogel addition improved water retention capacity in both the studied P1 and P2 substrata. Increasing hydrogel dose was accompanied by a progressive increase in water retention capacity and retention of available water for plants, whereas drainage capacity decreased in relation to the control treatments. Soil and tailings enriched with the hydrogel supplement revealed a lower rate of drying, which limits the loss of water available to plants. The applied hydrogel positively affected plant growth during drought stress. The presented investigations revealed that in drought conditions, young plants growing in the substrata without hydrogel were able to survive for a maximum of five days, whereas in the treatments with 0.2-1% hydrogel supplements they survived for up to 15 and 10 days in the case of P1 and P2, respectively. The plant survivability period during drought was extended by 66% on soil (P1) and by 39% on tailings (P2).