Bolgewas

Bolgewas is a term used in Dutch horticulture to describe crops that form an underground storage organ in the form of a bulb. In practice, it refers primarily to edible bulb crops, especially species in the Allium genus such as onion (Allium cepa), garlic (Allium sativum) and shallot (Allium cepa var. aggregatum). These bulbs store nutrients and serve as a means of asexual propagation. They differ from tuber crops (like potato) and from other root vegetables in the anatomy of the storage organ: onions consist of fleshy leaves arranged in layers, while garlic develops a bulb made of individual cloves.

Botany and propagation methods are distinctive for bolgewas. Onions and shallots can be grown from seeds or from sets and transplants, while garlic is typically propagated annually from individual cloves. Cultivation commonly requires well-drained soil, adequate fertility, and cool-to-mild growing seasons. In temperate regions, onions are often planted in early spring or autumn, garlic is usually planted in autumn, and shallots are grown under similar schedules. Regular mulching and careful irrigation help bulb development, while disease and pest pressures—such as onion thrips or onion maggot—are managed with integrated practices.

Harvesting and storage follow bulb maturity. Onions and shallots are typically lifted when tops begin to yellow and dry, cured in a warm, ventilated space, and then stored in cool, dry conditions. Garlic is harvested when foliage dies back, cured similarly, and stored for extended periods.

Bolgewas crops are of major importance worldwide for food production, culinary use, and agricultural livelihoods, with management focused on bulb quality, yield, storability, and resistance to pests and diseases.