Micron-size metal-binding hydrogel particles improve germination and radicle elongation of Australian metallophyte grasses in mine waste rock and tailings

► We synthesised micron-size thiol-functional cross-linked acrylamide particles (X3). ► X3 reduced toxic soluble metals in mine wastes to below the phytotoxicity threshold. ► X3 remarkably increased water holding capacity of mine wastes. ► X3 provided moisture to seeds during germination in water restricted conditions. ► X3 enhanced seed germination and radicle elongation in phytotoxic mine wastes.