High Tunnels For Vegetable Production

High Tunnels For Vegetable
Production- Updates for 2013
The NRCS EQIP Grant Program
• Environmental Quality Incentives Program
• Seasonal High Tunnel Initiative 2013
– In 2012 NRCS approved 227 applications around
– Have 1 year to implement the practice
– Only paid when the tunnel is completed
Seasonal High Tunnel Initiative 2013
• Three application deadlines
– Early Winter (Jan) and Early Spring (March/April)
• Rolling application deadline
• Cannot start purchasing until approved and
paperwork signed
Seasonal High Tunnel Initiative 2013
• The maximum size is 5% of 1 acre or 2178 ft2
– Realistically this means a 30 x 72 (2160 ft2) tunnel
• Do not pay for materials and supplies just
installation of equipment BUT you can install
– $2.37/ft2 so $5,162 for a 30 x 72 tunnel
– $2.84/ft2 for historically underserved ($6,286)
– Must be a kit from a manufacturer
Seasonal High Tunnel Initiative 2013
• Can be fixed or movable, but have different
payment schedule scenarios for each
• Supposed to have a 4 year life-span
– 4 year plastic not structure
– Within the 4 years you are responsible for repairs
to tunnel
– http://www.nrcs.usda.gov/wps/portal/nrcs/detailf
– Google “Eqip nrcs high tunnel”
Traditional Tunnels
Locating Tunnels
• For maximum and most uniform sunlight
interception locate tunnels in a N-S
orientation if at 40 oN or further south
• If above 40oN orient E-W
• If multiple bay tunnels then orient N-S
• In winter E-W orientation tends to capture
more light as sun is low in the horizon, but in
spring it is distributed poorly in E-W
Locating Tunnels
• Wind is also an issue
– High winds can destroy tunnels
– UPLIFT is important – anchoring tunnels
– Consider wind breaks
• Single bay high tunnels oriented perpendicular
to prevailing if structure has roll-up sides *
Multi-bay high tunnels should be oriented
parallel to prevailing winds
Tunnels and uplift
• Proper anchoring of tunnels is essential
– Tunnels are basically a giant wing
• An 80 mph wind blowing perpendicular to a
28’ x 100’ tunnel can create an uplift force of
22,000 pounds or 220 lbs per foot
• Estimated a 30 x 72 tunnel would then be
15,840 lbs of uplift
Anchoring tunnels
• Assuming a maximum of 16,000 lbs of uplift
– Subtract tunnel weight (2846 lbs without
baseboards, endwalls, etc)
– We need to account for about 13,000 lbs of
– 18 bows with 2 anchor points is 36 total contact
– 360 lbs per contact point of resistance or 720 lbs
per bow
Anchoring tunnels
• Should you concrete bows in? – yes for many
• “Earth Anchors”- 30” anchor 4” helix rated at
1500 to 2500 lbs vertical pull out
• “Telephone pole anchors”- rated at 14,000 lbs
Wind Damage to greenhouses- bows
anchored in concrete 70-80 mph
Wind Damage January 2013 ~ 35 mph wind
Wind Damage January 2013
High Tunnel Structural Supports
Lack of additional support
• 4 mil is considered 1 year plastic
• 6 mil is considered 4 year plastic– If it gets too hot >120 for a long period of time
that cuts life of the plastic
• Super Strong Woven Poly- 11mil
– Can outlast hail even and can be walked on
– Costs 30-50% more
• Shade cloth
– Is it worth it? Wouldn’t go more than 40%.
Infrared films
• IR films have a coating that block long-wave
radiation back into tunnel
– Typically this long-wave radiation goes right
through plastic unless a barrier is present
– One side of the plastic is coated with a film that
keeps long-wave radiation in
• Often coated with a wetting agent to reduce
Infrared films
• Bill Roberts (Rutgers Univ.) found that IR films
showed a heat savings of up to 35% on clear
cold days
– Realistically this will be 15-20% over the course of
a season (assuming a tightly sealed tunnel)
– Only use on the inside layer of plastic
• IR Cost 32’ x 100’ $304 vs. $256 for non IR
Tunnel temperatures
• Air-gap between twin
walled (2 layer plastic)
reduces energy loss by
• Energy loss due to
condensation will be
less on a 2 layer tunnel
High Tunnel Temp.
• When there is a lot of
condensation present,
which may evaporate,
temperatures in the
early morning may be
several degrees cooler
ambient outdoor temps
• Latent heat of
in a tunnel
End walls
• Double layer polycarbonate
has about the same R value
as double layer plastic
– Single layer plastic has a very
poor R value
End Walls
High Tunnel Venting
• Should have reasonable side walls for venting
• Ridge vents are not a great option
– Some complete ridge vents are good, but
• Taller tunnels tend to keep heat up away from
– HAF-Horizontal air flow fans
HAF Fans
HAF Fans
• Help bring hot air down to plant level
Note this
piece of
No Crop
3 feet tall tomato
6 foot tall tomato
Wind coefficients higher is more air flow
Indeterminate or Determinate
• The most critical decision
– Spacing will impact everything
• Disease, yield, working conditions, etc.
– Indeterminate – 4 square feet per plant for
trellised plants in a greenhouse*
• Based on lack of air movement and disease risk in
tunnels move to 5.2 - 6 square feet per plant
• 4 foot centers and 15-18 inch spacing
– Determinate –6.75 square feet per plant
• 4.5 ft centers with 18” in-row spacing
• This will give you 6-7 rows in a 30’ wide tunnel
5.5-6.0 feet
4.5 ft
Note- Indeterminate
plants pruned to a
central leader with
leaves removedfacilitates closer
Determinate tomatoes on 5’ centers
Pruning, training, etc.
• Typically prune
determinate plants as
you would in the field
– If you prune them to a
central leader you will
ruin your yields
• Indeterminate plants
off the ground
Cluster Pruning
• Cluster pruning
– Leave 4 fruit per cluster
early and then move to 5
– Prune off when pea size
– Typically do not want
more than 18-20 fruit on
a plant
• Truss hooks on
Leaf Pruning
• Keep 18-21 leaves on a
• Remove leaves up to
cluster being harvested
• Remove any senescing
• If too aggressive can rob
fruit of essential nutrients
– Depends on aggressiveness
of variety too
• Indeterminate
Big Beef
Trust (hydro)
Geronimo (hydro)
Heirlooms benefit from
the tunnel, but results
• Determinate
Rocky Top
BHN 589 (fall)
Primo Red
Red Deuce
Parthenocarpic Tomatoes
• Have done well in Mississippi
• Do not need pollinators
– Varieties (Territorial Seed)
Oregon Spring
Insect Management with
High Tunnel Tomatoes
High-Tunnel Insect Pests
Pests with Short-life cycles
Fosters the rapid development of resistance to some
Rapid recovery from sprays
Need to manage pests/pesticides
For safety
For resistance management
Opportunity for biological control
Controlled environment
Some of our best examples come from enclosed areas
Limited insecticides/miticides
Without GH restriction
Mustang max
Asana XL
Without GH restriction
• Admire
• Belay
• Venom
• AgriMek
• Distance/Knack
• Fulfill
• Dipel
• Courier
• Acramite
Limited insecticides/miticides
With GH prohibition
• Diazinon
• Endosulfan
• Assail
• Platinum/Actara
• Radiant
• Proclaim
• Beleaf
• Rimon
• Intrepid
With GH prohibition
• Avaunt
• Oberon
• Movento
• Coragen
• Portal
• Belt/Synapse
2012 Tomato Russet Mite
2012 Tomato Russet Mite
Tomato Russet Mite
Mistaken for other problems
Start at bottom of plant and work upward
Leaves dried out- ‘burned up’
Mite move quickly to green leaves – develops
Jessamine Co.
Tomato Russet Mite
• Life cycle of 5 to 6 days
• Feed on Solanaceous plants/weeds
• Can be moved by people or
• Scout for damage and confirm with
20x lens
• Treat with Agri-Mek or insecticidal
soap (low populations)
2012 Broad Mite
2012 Broad Mites (aka Tropical Mite)
Agri-Mek 0.15 EC
for broad and
tomato russet
mites when they
first appear
Broad mites: wide host range
found in and around the buds
complete life cycle in a week
Insecticidal soap
inject toxic saliva as they feed
hardened, twisted growth, leaves curl downward
peppers most susceptible
Spider Mites
• Two spotted spider mite
• Stippling of leaves and
gold flecking of fruit
• Produce fine webbing
• Favored by hot dry
• Tomatoes, beans,
melons, cucumbers
Casey Co - 2012
Spider Mites
Complete life cycle in 8+ days
Females lay 100+ eggs
Under leaves, around buds
Prefer tender leaves
– Look for stippling
– Look for webbing
Spider Mites
• Management
– Control weeds in/outside of GH/HT
– Monitor weekly with hands lens or tap leaves over
white paper
– Use horticultural oils or insecticidal soap for light
– Use Agri-Mek or Acramite for ↑ numbers
• Two types, greenhouse and silverleaf
Undersides of leaves
Complete life cycle in less than a month
Produce honeydew, stunt plants
Can transmit Yellow Leaf Curl Virus
Silverleaf can cause plant distortions
Whitefly Management
• Monitor weekly – tap plants
• Check undersides of leaves with hand lens
• Use biocontrol – Encarsia formosa (GHWF)or
Eretmocerus eremicus (SLWF) wasps
• Insecticides (IGRs) for
• Insecticides for adults and
Admire (foliar or systemic)
Venom (foliar or systemic)
Thrips in the High Tunnel
• Direct damage to tomato fruit – ‘gold fleck’
• Vectors of Tomato Spotted Wilt Virus
Thrips Life Cycle
Two protected stages
Thrips in the High Tunnel
• Pierce plant cells
• Mainly females
– 150 to 300 eggs each
– eggs inserted into leaves
• Resting stage in media
• Life cycle complete in 7 to 14 days
Thrips and Virus
• Vectors of TSWV
– Acquire when immature and transmit primarily as
– Transmit for life
– Acquire from infects crop plants or weeds
• Monitoring
– Yellow or blue sticky cards
– Tapping buds/flowers over white paper
– Avoid bright colored clothing
Thrips Management
• Limited insecticides to control thrips for the
high tunnel
– Baythroid (foliar)
– Brigade (foliar)
– Agri-Mek (foliar)
– Venom
• Second treatment?

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