Many oilseed rape growers could almost halve the seed they use if they sowed by seed number rather than weight, says ProCam Group technical manager Nick Myers.

The firm’s data show an average of 5-7kg/ha of seed used in the past two years, regardless of establishment method.

“Assuming a typical thousand grain weight of 4-5g/1000 seeds, this means between 110 and 150 seeds/sq m were sown. Current thinking suggests an optimum seed number for conventional varieties is 60-80 seeds/sq m to produce a final plant population of 30-40/sq m,” says Mr Myers.