We demonstrate a simple and novel approach for the low-temperature (400 degrees C) solid-state growth of ZnO micro- and nanorods directly front sol-gel-derived Al-doped ZnO films on silicon substrates without any catalyst. Hot pressing the films by a PDMS pad before annealing has been found to be effective for the creation of ZnO rods. A possible nucleation mechanism of ZnO rods has also been proposed.