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The
Hemp Plant
The
hemp plant is harvested for its fibers, seed,
seed meal and seed oil.
Hemp is a distinct variety of the plant
species cannabis sativa L. Due to the similar
leaf shape, hemp is frequently confused with
marijuana. Although both plants are from the
species cannabis, hemp contains virtually no
THC (delta-9-tetrahydrocannabinol), the
active ingredient in marijuana.
Hemp cannot be used as a drug because it
produces virtually no THC
(less than 1%), where marijuana produces
between 5 - 20 % THC. |
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Hemp
Agronomic Characteristics
Hemp
is a bast fiber plant similar to flax, kenaf,
jute and ramie. Long slender primary fibers
on the outer portion of the stalk
characterize bast fiber plants. An annual
plant that grows from seed, hemp can be grown
on a range of soils, but tends to grow best
on land that produces high yields of corn.
The soil must be well drained, rich in
nitrogen, and non-acidic. Hemp requires
limited pesticides because is grows so
quickly and attracts few pests. In northern
latitudes, hemp is usually planted between
early March and late May. Hemp averages
between 2 - 4 meters in height in about four
months of growth.
Hemp
crops are harvested at different times for
different hemp products.
- Harvesting
stalks for high quality primary fiber
occurs as soon as the crop is in
flower.
- Harvesting
for seed production and stalks occurs
4 - 6 weeks after flowering, when
male plants begin to shed pollen.
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Primary
Hemp Fiber
The
valued primary fibers are contained around
the hollow, woody core of the hemp stalk.
These
long, strong fibers that grow the length of
the hemp stalk are considered bast fibers
Hemp fiber possesses properties similar to
other bast fibers (flax, kenaf, jute and
ramie) and excels in fiber length, strength,
durability, absorbency, antimildew and
antimicrobial properties.
Once
a hemp crop has matured and been harvested,
hemp primary fibers are separated from the
hemp stalk through the "retting"
process. For "dew retting", the cut
stalks are left in the field for several
weeks to allow natural humidity and bacteria
to decompose the fiber-binding pectins. Other
ways to separate the fiber from the core are:
water retting, warm water retting and
chemical retting. When the retting process is
complete, the fibers are readily separated
from the core, and processed for specific
products.
Primary
fibers are long-staple length fibers,
averaging 8 ” (20 cm) in length. These
hemp fibers can be spun and woven to a fine,
crisp, linen-like fabric and used for apparel
textiles, home furnishing textiles and
carpeting. Antimildew and antimicrobial
properties make them very suitable for sails,
tarps, awnings, and floor coverings.
Primary
fibers can be cut to shorter staple lengths
to accommodate a variety of spinning systems.
Hemp fiber blended with wool, cotton, linen
or other fibers, adds strength, durability,
absorbency and breathability, making
hemp-blended fabrics cool and comfortable to
wear and touch.
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The Qualities of
Primary Hemp Fiber
| structure |
hemp
under microscope 125 x magnification
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| length |
average 8 ” (20
cm) in length,
4 - 6 ”, 1 - 2 ” and special
lengths available upon request |
| luster |
high |
| strength |
high |
| elasticity |
low, can be treated
to improve |
| heat conductivity |
high, very cool
fabric to wear |
| absorbency |
high |
| cleanliness and
washability |
high |
| reaction to bleaches |
will weaken, use
with care |
| reaction to heat |
will scorch and burn |
| effect of mildew |
highly resistant |
| effect of light
& outdoor exposure |
very resistant |
| reaction to alkalies |
not affected |
| reaction to acids |
easily affected |
| affinity for dyes |
very good |
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Core
Fiber
Core
fiber is derived from the sturdy, wood-like
hollow stalk of the hemp plant. Sometimes
referred to as "hurds", it is up to
twice as absorbent as wood shavings, making
it an excellent animal bedding and garden
mulch. It can be easily blended with lime to
create a strong yet lightweight concrete or
plaster. Its high cellulose content means it
can be applied to the manufacturing of
plastics. Like primary fiber, it is
biodegradable and possesses antimildew and
antimicrobial properties. |
U.S. Legal
Definitions
Custom Regulations
of the United States, Official US Custom House Guide,
1987. sec. 302.58 --CR-360. MARIJUANA STATUTORY
PROVISIONS
Controlled Substances Act, Food & Drug Admin
(1970)
Chapt. 22, Sec.
802-15 Definitions:
(a) MARIHUANA. The term 'marihuana' means all parts
of the plant Cannabis sativa (L.), whether growing or
not, the seeds thereof, the resin extracted from any
part of such plant; and every compound, manufacture,
salt, derivative, mixture or or preparation of such
plant, its seeds or resin;
BUT SHALL NOT INCLUDE the mature stalks of such
plant,. fiber provided from such stalks, oil or cake
made from the seeds of such plant., any other
compound, manufacture, salt, derivative, mixture or
preparation of such mature stalks (except the resin
extracted therefrom), fiber. oil or cake or the
sterilized seed of such plant. which is incapable of
germination.....
Resources:
Hemp Horizons by John Roulac, Chelsea Green
Publishing Company, 1997
Hemptech Inc.
Hempline Inc.
Agriculture and Agri-Food Canada
Photos courtesy
of:
Hemptech Inc.
Hempline Inc.
Hempbrokers.com
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