Agriculture Reference
In-Depth Information
Emergence (0 to 4-9 days)
Sowing
Em ergen ce
Occurs after approximately 80 GDD (growing degree days), which
is usually 4-9 days after planting depending on soil conditions. This
is the most critical phase of cultivation.
Establishment
Establishment (4-9 days to 3 weeks)
Slow growth phase of the crop during which the canopy is
established. It can take up to 3 weeks to establish the complete
canopy. At the end of this stage, the crop will measure 25-30 cm in
height and each plant will have three leaves.
Active growth
Active growth phase (3 weeks to 2.5 months)
Period falling between the end of establishment and initiation of
flowering. Fibre production takes place during this phase and
mineral and water demand is greatest and must be met. It is during
this period that the plant is most sensitive to lodging.
Beginning of flowering
Flowering
full flowering
The appearance of the first flowers in a hemp crop is related to the
total temperature during emergence and to the photosensitivity of
the variety. Growth slows during this period.
end of flowe ring
Full flowering
This stage corresponds to the opening of the last female flowers
and is strictly dependent on the photo period. A particular variety
grown in a particular zone will reach this point at a specific date,
irrespective of the date of sowing or of any variation in annual
conditions.
Seed maturity
End of flowering
Harvest
This is defined as the point at which the last flowers are pollinated.
This point marks the end of growth and determines the final yield of
fibre; it initiates the maturation of the fibre and seeds.
Seed maturity
This is obtained 40 days after full flowering. The harvesting will be
timed, however, to take into account the moisture level of the seeds
and the capacity of the driers (an essential stage) and this can lead
to considerable delays between this stage being reached and
actual harvest.
Fig. 5.1. Growth stages of Cannabis sativa L. according to the FNPC method.
loss accounts for the reduction in dry matter seen
at the end of the growth cycle.
Varieties start to show differences at the start
of flowering. Late maturing varieties show the
largest number of nodes. An increase in the
number of nodes is highly dependent on accu-
mulated heat units (GDD); no effect from
other influences (e.g. nitrogen) has ever been
shown.
Number of nodes
The number of nodes increases regularly from
the start of the growth cycle through flowering.
 
 
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