Twin-scaling is a method of
propagating 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 duri ...
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 ...
'' 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 amaryllis fa ...
'';
* 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 fair ...
'';
* ''
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
''Veltheimia'' is a genus of perennial plants native to the Cape Provinces of South Africa in the family Asparagaceae, subfamily Scilloideae
Scilloideae (named after the genus '' Scilla'', "squill") is a subfamily of bulbous plants within the ...
'' 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 Rome ...
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
Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...
(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 st ...
). 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
Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...
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 wea ...
, 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
illustrationof the twin-scaling technique
Horticulture
{{horticulture-stub