Growth and bulbing of garlic (Allium sativum L.) in response to storage temperature of planting stocks, day length, and planting date

Garlic is a condiment crop of limited use and fairly constant market demand. About half of the garlic consumed in the United States is grown domestically, and almost all of this in California where some 2,000 acres are grown each year. Although a minor crop, it has been an important source of income in local areas for many years.

Garlic growing is strictly seasonal; except for small differences among kinds of garlic and among growing areas, the cloves are planted in the winter months, start growth almost immediately, and form mature plants in late spring or summer. Despite this strong seasonal response, little has been known of the environmental factors controlling the pattern of growth. The present paper discusses field and greenhouse experiments which show that bulb formation and plant maturity are controlled primarily by the temperature to which plants are exposed, both before and after planting in the field, and by the changing length of day during the spring growing period. These factors are considered as they relate to cultural practices and to the quality of the crop.