Part
V Cut Flower Production |
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High
Tunnel v. Field Grown Cultural Practices |
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When
to Plant |
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•Considerations
to determine appropriate planting dates include target market
dates, plant type, and plant species |
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Examples
of target market dates include specific holidays like Mothers
Day vs. weekly delivery to a local florist |
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Annuals,
depending on species, can be planted as early as late winter
and as late as the summer |
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Biennials are often planted in the
fall to accommodate their need for a cold treatment requirement
to flower
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Perennials, depending
on the species, are planted
in the spring or fall
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•Field
Production Comparison: Spring planting in the
field must wait until all danger of frost has past. However,
high tunnels offer protection against spring frost and crops
can survive being transplanted several weeks earlier |
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| Plant
Spacing |
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•Plant
spacing depends on several factors, including plant species,
sensitivity to disease, method of staking, and method of harvesting.
Spacing distances range from 4" x 4" to 12" x
12" |
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•Field
Production Comparison: In
general, annuals can be spaced from 4" X 4" to 18"
X 18" apart and perennials from 12" X 12" to
24" X 24" apart |
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| Crop
Support |
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•Crop
support is important for production of cut flowers to reduce
breakage and increase quality of cut flower stems |
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The
most effective method to provide crop support is to use a
plastic, nylon or wire mesh with 4-6" openings that is
supported horizontally with wood or metal stakes. |
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Depending
on the final height of the stems and the species, two to three
layers of support may be required |
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Staking
plants individually is an inefficient use of labor and is
usually unnecessary with properly planned use of mesh supports |
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•Field
Production Comparison: Mesh support material that
is supported horizontally with wood or rebar stakes is also
used extensively in field production |
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| Watering |
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•Drip
irrigation is the preferred method for watering cut flowers
in high tunnels |
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There
are several types of drip irrigation, but use of T-Tape or
turbulent twin wall tape is very common |
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•Field
Production Comparison: Drip
irrigation is also widely recommended over overhead watering
for field production. Field-produced cut flowers will also obtain
moisture from rainfall: this is often a major drawback because
wet foliage contributes to foliar disease and heavy rains can
damage flowers and stems which decreases quantity |
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| Nutrition
Requirements |
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•Cut
flowers have high fertility requirements |
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Fertilizer
can be applied pre-plant as a granular formulation or during
production as a soluable feed
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Higher
rates of nutrition are required during the initial stages
of plant growth when vegetative growth is active, but as
harvest approaches lower rates if soluable fertilizer are
applied
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•Field
Production Comparison: Fertilization rate also
corresponds to the stage of plant development; however, heavy
rains may leach nutrients from soil in a field production situation |
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| Insect
& Mite Control |
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•Major
insect pests of cut flowers produced in high tunnels are aphids,
spider mites, thrips, and grasshoppers |
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•Other
pests include cutworms and leafminers |
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•Because
plastic coverings typically contain a UV-block to minimize polyethylene
degradation, bees, which require ultra-violet light to perceive
pollen, may not find flowers in high tunnels |
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This could be advantageous for crops like snapdragons where
florets die after pollination
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•Field
Production Comparison: The same insect pests will
thrive in the field; bees will readily pollinate flowers |
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| Disease
Control |
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Infectious
Disorders |
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•Infectious
disorders are diseases caused by bacteria, fungi, viruses
or insects |
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•Some
commonly found in cut flower production include: |
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•Root
Rots |
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Fusarium,
Pythium, Rhizoctonia, Phytophthora
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•Stem/Crown
Rots |
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Botrytis,
Rhizoctonia, brown rose canker, Sclerotinia
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•Foliar
fungus diseases are the most serious problem on cut flowers |
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Leaf
Spots is a broad category denoting diseases that disfigure
foliage
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Bacterial
Leaf Spots thrive in warm moist conditions and spread by
water splash, insects, or other physical manipulation
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Fungal
Leaf Spots are caused by Botrytis, Alternaria, Septoria
and thrive in cool periods
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Rusts
are also a fungus, and typically target specific species
and cultivars
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Downy
mildew is found on the underside of leaves: spores can remain
in the soil for many years, so remove infected plants as
soon as possible, provide adequate spacing, and avoid watering
leaf surfaces
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Powdery
mildew is the most prevalent and serious disease because
it can disfigure foliage and flowers; its growth is encouraged
by high humidity conditions
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•Viruses
are host specific: however, some have a very broad host range
such as the tospovirus impatiens necrotic spot virus (INSV)
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Viruses
are spread through propagation and insect vectors
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Control
of viruses is limited to removing the infected plant material
and controlling insect populations
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•Phytoplasma
is the casual agent of the disease commonly known as aster yellows
that affects a number of annual and perennial cut flowers |
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Aster
yellows is vectored by the aster leafhopper; control of
the insect and removal of the infected plant material is
the best form of control
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•Field
Production Comparison: Cut flowers are subject
to the same diseases in the field. Relative humidity is usually
higher in high tunnels which may contribute to higher incidence
of mildews. However, wet foliage and water-logged soils resulting
from heavy rains may increase incidence of root rots during
filed production |
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