Garlic is a unique and rewarding crop, prized for its flavor and longevity in storage. Unlike most vegetables grown from true botanical seeds, garlic propagation relies on planting vegetative material, which are genetic clones of the parent plant. Understanding how and when to harvest and prepare these structures ensures the best quality bulbs for the following planting season.
Understanding Garlic Propagation Material
Many gardeners use the term “garlic seeds,” but garlic rarely produces traditional botanical seeds. True garlic seeds result from sexual reproduction, primarily used by breeders to create new varieties. This method is difficult for the average home grower due to low viability (10 to 15%) and requires specialized techniques and a multi-year commitment to produce a usable bulb.
The two primary materials for propagation are cloves and bulbils, both involving asexual reproduction. Cloves are the individual segments found within the main underground bulb, and they are the most common and reliable planting material, yielding a full-sized bulb in a single season. Bulbils are tiny aerial cloves that form in the flower head, or scape, of hardneck garlic varieties and are often what people are referring to when they mention “garlic seeds.”
Harvesting Garlic Bulbils
Bulbils offer a clean, disease-free method of multiplying a variety, though it requires more patience than planting cloves. To harvest them, allow the scape to remain on the plant, refraining from the common practice of cutting it in early summer to encourage larger bulb growth. Bulbils are ready for harvest when the scape has fully matured, typically in late summer, and the cluster has expanded and split open the protective sheath.
Cut the entire scape head from the plant or wait until the plant begins to die back naturally. Once removed, the bulbils need a short drying period to prepare them for storage. Spread the clusters in a single layer in a well-ventilated area, away from direct sunlight, for a few days to condition them. When planted in the fall, these bulbils produce small, single-cloved bulbs (“rounds”) in their first year, which are then replanted to yield a full, segmented bulb in the second season.
Harvesting and Curing the Main Bulbs
The main underground bulbs require precise timing for harvest. The best indicator is the plant’s foliage, which signals when the bulb has finished sizing up and the protective outer wrappers are beginning to dry. Growers aim to harvest when approximately half of the lower leaves have yellowed and died back, leaving four to six green leaves still active at the top of the plant.
Harvesting too early results in small bulbs that have not reached their full potential, while waiting too long causes the mature bulb to split its protective wrappers underground, which greatly reduces its storage life. When the timing is right, resist the temptation to pull the plants by the stem, as this can easily separate the stem from the bulb. Instead, use a garden fork or spade to gently loosen the soil several inches away from the plant, carefully lifting the entire bulb, stem, and roots from the ground.
After harvest, gently brush away the excess soil from the bulbs, taking care not to scrape or wash them, as moisture can encourage mold and rot during curing. Curing prepares the bulbs for long-term storage and subsequent replanting. The bulbs, with their leaves and stems still attached, must be dried in a dark, warm, and well-ventilated space, such as a shed or covered porch.
This drying process typically takes between three and six weeks, depending on the humidity and air circulation of the curing area. During this time, the protective wrappers around the bulb constrict and develop a papery, parchment-like texture, sealing the cloves inside. Curing is complete when the stem near the bulb is completely dry and firm, a structure that helps prevent the entry of pathogens and moisture, ensuring the cloves remain viable for planting in the fall.