To reduce the size of seed hemp plants, the effects of different delayed sowing dates (30 April, 31 May and 30 June) were investigated in 1999 and 2000 combined with chemical (Cycocel and Ethrel) and mechanical (polling) treatments. The trials were carried out at Anzola Emilia (Bologna) using the variety 'Carmagnola'. Each chemical treatment was repeated three times at two-week intervals starting from the appearance of the 6th true leaf. Polling was performed by manually removing 60 cm from the top of plants, once a height of 150 cm was reached. Late sowing was found to be very effective in reducing the size of the plant, however the latest date (30 June) is not recommended due to its negative effect on seed production (-32%). Ethrel, unlike Cycocel, produced shorter plants and also, unfortunately, fewer seeds. Polling was slightly less effective than Ethrel in reducing plant height, although it tended to produce more seeds than the control.