Twin-scaling is a method of propagating plant bulbs that have a basal plate, such as: Twin-scaling is practiced by professional growers and skilled amateurs to increase bulbs that would naturally propagate very slowly, or to speed up the production of desirable cultivars.
[citation needed] The dormant bulb which is to be twin-scaled has its surface sterilized by removing its dry tunic and carefully trimming off its roots and any dead tissue, while leaving a layer of sound basal plate intact, then dipping the clean bulb in dilute bleach (or another suitable disinfectant).
True twin-scaling involves further subdivision of the chips to create pairs of scales, joined by a small part of the basal plate.
The twin-scales are then treated with fungicide before being mixed with moist, sterile Vermiculite, sealed in plastic bags and left in a fairly warm, dark location until new bulblets form.
Some species may require alternate periods of warm and cool storage to initiate bulblet growth.