Garlic (Allium sativum L.) plants were grown in pots using drip fertigation in a greenhouse. In Experiment 1, growth and development of root, leaf and bulb were compared. The decrease in root dry weight, which was similar to that in the leaves, started after the appearance of the last leaf, i.e. in the middle of the bulb growth period. In Experiment 2, nitrogen deprivation, at the beginning of bulb growth or at the onset of leaf and root senescence, was compared with a continuous nitrogen supply until harvest. Early nitrogen deprivation speeded up and increased the redistribution of the organic nitrogen of leaves and roots to the bulbs, and decreased the nitrogen content of the bulb. Bulb weight was little affected. Nitrogen was slightly favourable to bulb growth and quality until the beginning of senescence, then slightly unfavourable.