Data from two laboratory-based studies, both investigating the interactive effects of abiotic and biotic controls on peatland carbon cycling. Data comprise carbon dioxide and methane fluxes in peat, litter mass remaining and respiration rate data from litter bags on peat mesocosms, and biochemical and physical properties of peat. Data was collected in from the first laboratory study, which focused on identifying the interactive effects of small-scale temperature change, water table level and plant functional type legacy effects in peat on carbon dioxide (CO2) and methane (CH4) fluxes from peat collected from Black Law Wind Farm, Lanarkshire, Scotland. Data includes CO2 and CH4 fluxes from peat mesocosms (sampled in May 2011), measured six times from October 2011 to September 2012. Data collected from the second laboratory study between October 2012 and October 2013 focused on identifying the interactive effects of small-scale temperature change and plant functional type legacy effects in peat and litter on decomposition in peatlands, and included litter mass remaining (% of initial litter mass) and respiration rate data from litter bags on peat mesocosms. Peat and litter used in this laboratory study were collected from blanket bog peatland at Black Law Wind Farm, Lanarkshire, Scotland in October 2012. Peat and litter used in both studies were analysed for their biochemical and physical properties. Biochemical and physical properties data for the first laboratory study includes bulk density, pH, total carbon (C) content, total nitrogen (N) content, ratio of C to N, C stock, N stock, total phospholipid fatty acids (PLFAs), total fungal PLFAs, total bacterial PLFAs, ratio of fungal to bacterial PLFAs, total gram-positive bacterial PLFAs, total gram-negative bacterial PLFAs and ratio of gram-positive to gram-negative bacterial PLFAs of peat. Biochemical and physical properties data for the second laboratory study include total carbon (C) content, total nitrogen (N) content and the ratio of C to N for peat and litter. Biochemical and physical data properties for peat and litter were used to better understand the effects of plant functional type legacy on greenhouse gas fluxes and litter decomposition. Full details about this nonGeographicDataset can be found at https://doi.org/10.5285/e15fbbab-1cdd-4509-81a3-aa050e927dd0