Between 1964 and 1966 thirty-one field trials were completed in twelve factory areas of the British Sugar Corporation to examine the feasibility of using mechanical thinning in conjvinction with low seed rates (3–6 in spacing) and chemical weed control to minimize the demand for labour in the spring. The results showed that where chemical weed control was effective in machine-thinned crops no hand labour was required for establishment, but there were mean losses in yield of 1·3 tons per acre (7%) compared with similar crops that were hand singled. These losses in yield were unaffected by variations in seed rates. Mechanical harvesters worked more efficiently in low seed rates, especially where monogerm seed was used.