Data comprises of the uptake of the plant nutrient phosphorus (P) by seven common and often co-occurring herbaceous plants grown in limestone grassland soil in pots. P uptake is from one of three different sources of P that were injected into the soil, with the P sources being labelled with radio-isotope 33P, such that uptake of this could be quantified by assessing the radioactivity of the plant tissue. The plant species were grown in pots as monocultures, and as mixed communities containing all seven species. The 33P labelled P sources that were injected into the soil were orthophosphate, DNA and calcium phosphate. Assessment of the amount of 33P taken up was undertaken by harvesting and analysing plant shoots six days after the 33P source was injected into the soil. The datasets contain biomass of the harvested plant material, its radioactivity as assessed by scintillation counting, and the calculated proportion of the 33P supplied that was taken up into plant shoots. The data also contains % cover abundance values of the plant species from surveys undertaken at Wardlow Hay Cop, the limestone grassland from where the soil was sourced on which the plants were grown for the 33P addition study. Full details about this dataset can be found at https://doi.org/10.5285/87cdc267-a8c7-4f59-83b4-1bceaae837ad