Vascular plant and bryophyte survey data from a 33-year chronosequence on bare chalk, used to investigate primary succession. The bare chalk plots were created from archaeological excavations on Down Farm, north Dorset, between the years 1986 and 2018, resulting in 13 different plots. The vascular plant survey was carried out in July 2019 using 50 cm x 50 cm quadrats. Quadrats were recorded every 1 m along a 16 m transect in each of the 13 plots. The bryophyte survey was carried out in February 2020 using 20 cm x 20 cm quadrats, along the same transects for 11 of the 13 plots.