Abstract The nettle (Urtica dioica L.) was grown in the substrate contaminated by the addition of fluoride (F−) (0, 50, 100, 200, 300, 400, 500, and 600 mg NH4F kg−1 substrate, respectively) in a pot experiment under controlled conditions. Stress syndrome response, accumulation of fluorine (F) and phytoremediation potential of the nettle were considered. At the end of the experiment the F contents in the nettle were up to 19-times higher in comparison to the typical background contents in the plants ( roots > stems. The F contents and masses per plant in dependence on the F− contents of the substrates were fitted to the polynomial functions of degree three. The inflection points of the polynomials located at ≈200 mg NH4F kg−1 substrate (corresponding to 14.1 mg F− kg−1 substrate) indicated the alarm phase of the nettle and were in agreement with the morphological observations. Significantly lower F− contents of the substrates in comparison to the control substrates at the end of the experiment were ascribed to the F− uptake by the nettle. Flowering, high biomass production, BAF > 4.7 and TF > 1.4 through the entire treatment range of substrate with NH4F, despite appearance of the necrotic lesions at NH4F treatments ≥100 mg kg−1 substrate (corresponding to 8.2 mg F− kg−1 substrate), were ascribed to the changes in the normal physiology and effective development of the stress tolerance mechanisms of the nettle. Use of the nettle as a passive bioindicator for monitoring soil pollution with F− or for the phytoremediaton by the mechanism of phytoextraction of F− polluted soils were suggested.