Garlic (Allium sativum) is botanically a perennial herb, but it is cultivated across the globe as an annual crop, completing its life cycle in a single growing season. The process begins not with a seed, but with a single clove, meaning the plant is propagated almost entirely asexually. The two primary groups, Hardneck and Softneck, share this fundamental life cycle, though they express different growth patterns during the development stages.
Initiation of Growth Planting and Cold Requirements
The beginning of the garlic life cycle is strategically timed for the fall, giving the individual planted clove a chance to establish a robust root system before the deep cold sets in. Each clove is planted with the pointed side facing up, and the flat basal plate, where roots emerge, facing down. This initial phase of root development is important for anchoring the plant and preparing it to absorb nutrients and water once spring growth begins.
A prolonged period of cold exposure, known as vernalization, is required for a successful harvest. Garlic needs this chilling period to trigger the internal switch that causes the single planted clove to differentiate and form a multi-clove bulb. Without sufficient cold, which typically requires six to eight weeks of temperatures below 40°F, the plant may only produce a single, undivided round bulb.
In colder climates, this requirement is met naturally over the winter months, with the clove remaining dormant but chilled beneath the soil surface. This ensures the necessary physiological change for bulbing occurs before the plant resumes active growth in the spring. Gardeners in warmer regions often have to simulate this process by chilling cloves in a refrigerator for 40 to 60 days prior to planting.
Above Ground Development and Scape Formation
As temperatures rise and day length increases during the spring, the garlic plant shifts into its vigorous vegetative stage, pushing green shoots upward. The plant grows a series of leaves that act as solar panels, capturing energy through photosynthesis and storing it for the final stage of bulb swelling. The overall size and health of the leaves directly determine the potential size of the mature bulb underground, as each leaf corresponds to a wrapper layer around the developing bulb.
During this period, a difference emerges between the two main types of garlic. Hardneck varieties, which are generally better adapted to colder climates, produce a rigid central flower stalk called a scape. Removing the scape is a common practice because it redirects the plant’s energy and resources away from reproduction and back into the underground bulb, thereby increasing the final bulb size.
Softneck varieties, which are better suited for warmer climates, do not produce this rigid scape, resulting in a flexible neck that allows them to be braided after harvest. The absence of a scape means Softnecks dedicate all their spring energy to leaf and bulb growth without the need for pruning.
Bulb Maturation Harvesting and Storage
The final weeks of the life cycle are dedicated to bulb maturation, where the energy stored in the leaves translocates downward to swell the underground bulb. The visual cue for this energy shift is the progressive browning and yellowing of the lower leaves. Growers typically aim to harvest when the lower third to half of the leaves have dried out, while the upper leaves still retain some green color.
Harvesting at the correct moment is important because waiting too long causes the bulb to split, compromising the protective outer wrappers and reducing its storage life. To avoid damage, the bulbs are carefully lifted from the soil, often by loosening the surrounding dirt with a digging fork. The entire plant, including the bulb, stem, and roots, is kept intact immediately following harvest.
Curing is the process of drying the bulb and its protective layers to prepare it for long-term dormancy. Curing involves hanging the whole plants in a dark, dry, and well-ventilated location for two to three weeks. This process dries the outer wrappers into the characteristic papery skin, seals the neck of the bulb, and stops the growth cycle. Once the stalk is completely dry and the outer layers are crisp, the roots and stem are trimmed, and the cured garlic is ready for storage.