Twin-scaling is a method of

propagating Plant propagation is the process by which new plants grow from a variety of sources: seeds, cuttings, and other plant parts. Plant propagation can also refer to the man-made or natural dispersal of seeds. Propagation typically occurs as a step i ...

plant

bulb In botany, a bulb is structurally a short stem with fleshy leaves or leaf basesBell, A.D. 1997. ''Plant form: an illustrated guide to flowering plant morphology''. Oxford University Press, Oxford, U.K. that function as food storage organs du ...

s that have a basal plate, such as: * ''

Hippeastrum ''Hippeastrum'' () is a genus of about 90 species and over 600 hybrids and cultivars of perennial herbaceous bulbous plants. They generally have large fleshy bulbs and tall broad leaves, generally evergreen, and large red or purple flowers. ...

'', '' Narcissus'', ''

Galanthus ''Galanthus'' (from Ancient Greek , (, "milk") + (, "flower")), or snowdrop, is a small genus of approximately 20 species of bulbous perennial herbaceous plants in the family Amaryllidaceae. The plants have two linear leaves and a single s ...

'' and other members of the ''

Amaryllidaceae The Amaryllidaceae are a family of herbaceous, mainly perennial and bulbous (rarely rhizomatous) flowering plants in the monocot order Asparagales. The family takes its name from the genus '' Amaryllis'' and is commonly known as the amaryl ...

''; * some members of the lily family ''

Liliaceae The lily family, Liliaceae, consists of about 15 genera and 610 species of flowering plants within the order Liliales. They are monocotyledonous, perennial, herbaceous, often bulbous geophytes. Plants in this family have evolved with a f ...

''; * ''

Lachenalia ''Lachenalia'' is a genus of bulbous perennial plants in the family Asparagaceae, subfamily Scilloideae, which are usually found in Namibia and South Africa. Most of them have a dormancy period, but new roots will always grow every year. ''Lache ...

'', '' Veltheimia'' and other members of the ''

Hyacinthaceae Scilloideae (named after the genus '' Scilla'', "squill") is a subfamily of bulbous plants within the family ''Asparagaceae''. Scilloideae is sometimes treated as a separate family Hyacinthaceae, named after the genus ''Hyacinthus''. Scilloideae o ...

''.

Purpose

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

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

s. Using twin-scaling, it is possible to multiply one bulb into 16 to 32 (or more) viable bulbs in a couple of years, whereas natural propagation might only lead to a doubling every two years or so. It is one of a number of propagation techniques (such as "scooping", "scoring" and "chipping") based on the fact that an accidentally damaged bulb will often regenerate by forming small bulblets or bulbils on the damaged surface. Commercial growers have obtained as many as 100 twin-scales from a single bulb.

Method

The dormant bulb which is to be twin-scaled has its surface sterilized by removing its dry

tunic A tunic is a garment for the body, usually simple in style, reaching from the shoulders to a length somewhere between the hips and the knees. The name derives from the Latin ''tunica'', the basic garment worn by both men and women in Ancient Rom ...

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 A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than s ...

). The bulb is then sliced cleanly from top to bottom several times, creating 8 or 16 segments, depending on the size of the bulb. At this stage, the segments are called "chips" (many growers are content with simply chipping a bulb into 4 or 8 and do not divide the bulb further). 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 Vermiculite is a hydrous phyllosilicate mineral which undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently, and commercial furnaces can routinely produce this effect. Vermiculite forms by the we ...

, 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. The tiny bulbs are planted into pots or trays of compost and allowed to grow on for a year or more, until they are large enough to survive in individual pots or the open ground. They usually take several years to reach flowering size, although some bulblets of ''Galanthus'' have been known to flower in their first year.

References

External links

* A step by ste
illustration
of the twin-scaling technique Horticulture {{horticulture-stub