If you fancy onions as big as footballs, early January is the traditional time to sow them. Early sowing ensures that maximum foliage growth is achieved early in the year. When day-length reaches 16 hours (some time in May), growth switches from the foliage to the bulb, which - fed by the green leaves - starts to swell. Big foliage means big onions.
Sow seeds in a tray of moist (but not sodden) seed compost at about 13
Celsius and keep in a light place (ideally a greenhouse). Transplant the seedlings while they are still curled over like shepherds' crooks, into individual pots or into another seed tray with slightly richer compost.
In late April, harden off. Plant outdoors in May in a fertile soil, if possible under protection for a few weeks. Space about a foot apart, with the base of the onion an inch below the ground, Don't feed after the end of June, and keep well watered during the summer.
Seeds for mammoth vegetables (including leek, celery, cabbage, parsnip, carrots and pumpkins, as well as onions) are available from W. Robinson and Sons, Sunny Bank, Forton, Nr Preston, PR3 0BN. Tel: 0044-1524-791210.
