A series of experiments was conducted at three contrasting sites (Cambridge University Farm, Gleadthorpe and Terrington Experimental Husbandry Farms) in four years (1985-88) to examine the effect of site, season and husbandry on growth and water use of the potato variety Record. Crisp processing quality was assessed at harvest and after periods of storage. Confounding of site and season with husbandry was avoided by maintaining similar husbandry in one experiment common to all sites and seasons. In 1989 at Cambridge, crops were grown in polythene tunnels to determine the effect of controlled water input on the number of tubers and efficiency of water use. Growth, development and yield of crops with similar husbandry generally did not differ between sites and seasons. Effects of husbandry (e.g. date of planting and date of harvest) at each site in all years were generally large compared with site and season effects. However, physiological age of seed tubers and irrigation regime had very little effect. Intercepted radiation was converted to tuber dry matter with greater efficiency in 1987 at Gleadthorpe than at the other two sites. In 1987, there was no effect of site on water use (evapotranspiration) efficiency with respect to tuber dry matter production, but later plantings used water more efficiently than early plantings. In 1988, the early planting at Gleadthorpe used water more efficiently than a similar date of planting at Cambridge. Excluding rainfall and withholding irrigation increased water use efficiency in 1989, and yield was lower from a crop kept close to field capacity than one which received the same amount of water over the season, but at less frequent intervals. Restricting crop water availability to soil reserves reduced the number of tubers greater than 10mm, but irrigation regime had no consistent effect on the number of tubers initiated or retained where rainfall input could not be controlled. Water uptake was related to depth and density of rooting, and date of planting and irrigation regime had considerable effects on root distribution. There were interaction effects between site and season on crisp fry colour. Delayed harvest resulted in darker crisps, but fry colour after long-term storage (36-40 weeks) could not be predicted from the colour at harvest. No significant correlation could be established between individual, or total, tuber sugar concentration and crisp colour.