Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
CONSIDERATIONS
The High Tunnel:
Patrick Byers
Regional Horticulture Specialist
University of Missouri Extension–Greene
Cou...
MY THANKS…
 Tim Baker, MU Extension
 LU Extension colleagues
 Several high tunnel growers
High Tunnel Environment
WHAT IS IN YOUR CONTROL?
Internal
Modification
s
Crop
Selection
Tunnel
Design
Tunnel
Orientation
S...
High Tunnel Defined6
“A HIGH TUNNEL [A.K.A. HOOPHOUSE] IS A
SOLAR HEATED, MANUALLY VENTED, PLASTIC
COVERED COLD FRAME THAT...
WHAT’S BEING GROWN?
SITE SELECTION AND ORIENTATION
 Close to your home
 Close to your fields and production areas
 Irrigation source
 Elec...
SINGLE HIGH TUNNELS
 Above 40°N latitude, orient the length of a
single high tunnel east to west
 This orientation allow...
GUTTER CONNECTED TUNNELS
 Gutter-connected tunnels at all latitudes
should be oriented north to south
 This orientation ...
WHERE ARE YOU LOCATED?
SITE SELECTION AND ORIENTATION
 A Critical Detail for Maximizing Productivity
 At our latitude (37 degrees north) either...
NORTH/SOUTH ORIENTATION AND CROPS
• Plant tall crops on the east side of the tunnel
• Ex: Peppers on east side of tomatoes...
EAST/WEST ORIENTATION AND CROPS
• North side gets shaded with taller crops to the South
• Planted tallest plants in the No...
SITE SELECTION AND ENVIRONMENTAL CONTROL
 Light (cont.)
 Avoid shadows cast from trees, adjacent high
tunnels or other b...
Source: Gene Giacomelli – University of Arizona
SITE SELECTION AND ENVIRONMENTAL CONTROL
 Air movement
 Air flow is used to modulate temperature and relative humidity
i...
CHALLENGES
 Season extension
 Spring, fall, winter
crops
 Low temperatures
 Low light conditions
 Low relative humidi...
SOIL MANAGEMENT
 Challenges of high tunnel production in the
Midwest
 may prevent the leaching effect of rain which incr...
RAISED BEDS
 Increase soil
temperature
 Improve drainage
 Enhance soil volume
for root system
 Size
 6 – 10” high and...
BENEFITS OF PLASTIC MULCHES
 Increased yields
 Earlier maturing crops
 Higher quality crops
 Enhanced insect
managemen...
PLASTIC MULCH COMPARISON6
SOIL FERTILITY MANAGEMENT
 Why is the tunnel environment different than
the field?
 Raised beds and drip irrigation tend...
FERTILITY MANAGEMENT
 Successful fertility management in the high
tunnel is related to several key components:
 Soil Tes...
LIGHT REQUIREMENTS
 Intensity
 Double outer layer of polyethylene will reduce
light intensity (outermost = 6 mil, inner ...
TEMPERATURE AND MULTIPLE PLASTIC LAYERS
 Double layer poly
 Dead air space provides insulation
 Inflating devices may b...
INTERNAL COVERINGS
 Think of this as a very wide double layer
of poly
 More insulating effect
 Many approaches to this ...
ROW COVERS
 Lightweight, spun bonded polypropylene
“blankets” supported over the crop row with wire
hoops4
 Permeable to...
ROW COVERS6
Source: Gene Giacomelli – University of Arizona
Source: Gene Giacomelli – University of Arizona
Source: Gene Giacomelli – University of Arizona
VENTILATION
 High tunnel position
 Perpendicular to prevailing
winds
 Lower temperatures
 Reduce relative humidity
 T...
EARLY SEASON TEMPERATURE TRENDS6
COOLING YOUR GREENHOUSE/HIGH TUNNEL
 Natural ventilation
 Ridge vents
 Side curtains
 End wall ventilation
 Shade clo...
NATURAL VENTILATION
Source: Greg Brenneman – Iowa State University
NATURAL VENTILATION
Source: Greg Brenneman – Iowa State University
AUTOMATIC VENT OPENER
Source: Greg Brenneman – Iowa State University
VENT DOOR WITH AIR CYLINDER
Source: Greg Brenneman – Iowa State University
Shading - reduce energy absorbed
a. Shade curtain
 Fabric over top of greenhouse/tunnel
 Degree of shading – depends on ...
REGULAR SEASON TEMPERATURE TRENDS6
GEOTHERMAL COOLING AND HEATING
 Pipes run underground
 Air drawn through pipes by blower
 Ground is cool in summer, the...
ACTIVE HEATING
 Portable heating units
•50-90% RH generally
•Plants, wet soils and
floors provide humidity.
•Mostly worry about
disease promotion.
•Vent or heat ...
Keep The Air Moving
Source: Greg Brenneman – Iowa State University
GOOD AIR CIRCULATION IS CRITICAL
Source: Greg Brenneman – Iowa State University
CENTER DUCT FOR CIRCULATION
Source: Greg Brenneman – Iowa State University
AIR CIRCULATION DUCT WITH HYDRAULIC MOTOR
Source: Greg Brenneman – Iowa State University
CULTURAL PRACTICES TO IMPROVE AIR CIRCULATION
 Stake and
weave
system6
CULTURAL PRACTICES TO IMPROVE AIR CIRCULATION
 Pruning
REFERENCES
1. Bartok, John W. et al. Production of Vegetables,
Strawberries and Cut Flowers Using Plasticulture.
NRAES-133...
QUESTIONS & DISCUSSION
Patrick Byers
Regional Horticulture Specialist
417-881-8909
byerspl@missouri.edu
HIGH TUNNEL INTEGRATED PEST MANAGEMENT
Source: Ted Cary, Lewis Jett, et. al.
TECHNIQUES TO REDUCE TEMPERATURE
Evaporation of Water
- Needs relatively dry air
- Foggers
 Requires fine nozzles, high p...
Source: Ted Cary, Lewis Jett, et. al.
SITE SELECTION AND ENVIRONMENTAL CONTROL
 Light
 Good sunlight is needed, especially early and late in the
season
 Calc...
HOW A PLANT GROWS
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Byers intermediateht
Upcoming SlideShare
Loading in …5
×

Byers intermediateht

19 views

Published on

American Small Farm Conference 2017

Published in: Education
  • Be the first to comment

  • Be the first to like this

Byers intermediateht

  1. 1. CONSIDERATIONS The High Tunnel: Patrick Byers Regional Horticulture Specialist University of Missouri Extension–Greene County Humidity Temperature Light
  2. 2. MY THANKS…  Tim Baker, MU Extension  LU Extension colleagues  Several high tunnel growers
  3. 3. High Tunnel Environment WHAT IS IN YOUR CONTROL? Internal Modification s Crop Selection Tunnel Design Tunnel Orientation Site Selection Ventin g Productio n Practices
  4. 4. High Tunnel Defined6 “A HIGH TUNNEL [A.K.A. HOOPHOUSE] IS A SOLAR HEATED, MANUALLY VENTED, PLASTIC COVERED COLD FRAME THAT IS USED TO LENGTHEN THE TRADITIONAL GROWING SEASON FOR MANY HORTICULTURAL CROPS.”
  5. 5. WHAT’S BEING GROWN?
  6. 6. SITE SELECTION AND ORIENTATION  Close to your home  Close to your fields and production areas  Irrigation source  Electricity  Orientation
  7. 7. SINGLE HIGH TUNNELS  Above 40°N latitude, orient the length of a single high tunnel east to west  This orientation allows low angle light from the winter sun to enter from the side where it will not be blocked by ribs of the frame  Below 40°N latitude, orient the length of a single high tunnel north to south  This orientation is acceptable because the angle of the winter sun is much higher at these latitudes
  8. 8. GUTTER CONNECTED TUNNELS  Gutter-connected tunnels at all latitudes should be oriented north to south  This orientation avoids the shadow that would occur from the tunnel just to the south of it in an east-west layout
  9. 9. WHERE ARE YOU LOCATED?
  10. 10. SITE SELECTION AND ORIENTATION  A Critical Detail for Maximizing Productivity  At our latitude (37 degrees north) either direction is acceptable as regards sun exposure
  11. 11. NORTH/SOUTH ORIENTATION AND CROPS • Plant tall crops on the east side of the tunnel • Ex: Peppers on east side of tomatoes produced less than on peppers on the west side of the tomatoes
  12. 12. EAST/WEST ORIENTATION AND CROPS • North side gets shaded with taller crops to the South • Planted tallest plants in the North rows
  13. 13. SITE SELECTION AND ENVIRONMENTAL CONTROL  Light (cont.)  Avoid shadows cast from trees, adjacent high tunnels or other buildings  Trees and structures on all sides of the high tunnel should ideally be set back 2.5 times their height  As a rule of thumb, multiple single bay high tunnels in an east-west orientation should be 20’ apart  As a rule of thumb, multiple single bay high tunnels in a north-south orientation can be as close as 4' apart  Locating high tunnels north of major structures is an undesirable siting
  14. 14. Source: Gene Giacomelli – University of Arizona
  15. 15. SITE SELECTION AND ENVIRONMENTAL CONTROL  Air movement  Air flow is used to modulate temperature and relative humidity in the high tunnel through ventilation of the end and side walls  Single bay high tunnels can be oriented perpendicular to prevailing winds to accommodate maximum air flow if structure has roll-up sides  Multi-bay high tunnels should be oriented parallel to prevailing winds  Prevailing winds are generally from the south-west in the summer and from the north in the winter, but specifics must be determined for each site  Windbreaks can be used to moderate or redirect wind  Sites located within 15,000 feet of large open bodies of water are exposed to very severe winds
  16. 16. CHALLENGES  Season extension  Spring, fall, winter crops  Low temperatures  Low light conditions  Low relative humidity  Regular season  Summer  High temperatures  High light conditions  High relative humidity flyingtomato.wordpress.com missouribeginningfarming.blogspot.com
  17. 17. SOIL MANAGEMENT  Challenges of high tunnel production in the Midwest  may prevent the leaching effect of rain which increases nutrient retention but also requires a more intensive management of nutrient/mineral balance (salts buildup)  could lead to limited crop rotation that favors development of root pathogens,  can result in soil compaction depending on management methods  usually accelerates weed/competitor/ground cover growth like crop growth but can limit the introduction of non-crop seeds
  18. 18. RAISED BEDS  Increase soil temperature  Improve drainage  Enhance soil volume for root system  Size  6 – 10” high and 24 – 36” wide blog.magiclandfarms.com
  19. 19. BENEFITS OF PLASTIC MULCHES  Increased yields  Earlier maturing crops  Higher quality crops  Enhanced insect management  Weed control  Reduce moisture loss
  20. 20. PLASTIC MULCH COMPARISON6
  21. 21. SOIL FERTILITY MANAGEMENT  Why is the tunnel environment different than the field?  Raised beds and drip irrigation tend to concentrate root systems  Nutrients are delivered via fertigation, and are readily available and mobile  The nutritional status of the soil and the plant are dynamic and can change rapidly  Excess nutrients often remain in the rooting zone following a cropping cycle, and can accumulate
  22. 22. FERTILITY MANAGEMENT  Successful fertility management in the high tunnel is related to several key components:  Soil Testing. Soil testing to determine the nutrient availability (pH) and balance is perhaps even more important than it is in the field.  Compost. Compost seems to be the most important soil fertility management tool for the high tunnel.  Rotations. The variation in crops grown in the tunnel will influence whether cover crops are needed to maintain soil fertility and health.
  23. 23. LIGHT REQUIREMENTS  Intensity  Double outer layer of polyethylene will reduce light intensity (outermost = 6 mil, inner = 4 mil)  Shade cloth used to reduce light intensity and heat in some crops  Trellising will improve light interception  Quality  Site selection  Duration and site selection  Winter vs. summer months
  24. 24. TEMPERATURE AND MULTIPLE PLASTIC LAYERS  Double layer poly  Dead air space provides insulation  Inflating devices may be AC, DC solar electric, air driven motors, or wind-driven passive systems
  25. 25. INTERNAL COVERINGS  Think of this as a very wide double layer of poly  More insulating effect  Many approaches to this idea
  26. 26. ROW COVERS  Lightweight, spun bonded polypropylene “blankets” supported over the crop row with wire hoops4  Permeable to light, water and air  Retains the warmth of soil after it has been heated by solar radiation  Expect a 2 – 8ºF increase in temperature under cover  Typical thickness/weight used  Light to medium weight = 0.5 – 0.9 ounces/square yard
  27. 27. ROW COVERS6
  28. 28. Source: Gene Giacomelli – University of Arizona
  29. 29. Source: Gene Giacomelli – University of Arizona
  30. 30. Source: Gene Giacomelli – University of Arizona
  31. 31. VENTILATION  High tunnel position  Perpendicular to prevailing winds  Lower temperatures  Reduce relative humidity  Threshold = 80% RH for most crops  Prevent spread of disease  Promote pollination extension.missouri.edu pubs.ext.vt.edu
  32. 32. EARLY SEASON TEMPERATURE TRENDS6
  33. 33. COOLING YOUR GREENHOUSE/HIGH TUNNEL  Natural ventilation  Ridge vents  Side curtains  End wall ventilation  Shade cloth or sprayed material  Active cooling
  34. 34. NATURAL VENTILATION Source: Greg Brenneman – Iowa State University
  35. 35. NATURAL VENTILATION Source: Greg Brenneman – Iowa State University
  36. 36. AUTOMATIC VENT OPENER Source: Greg Brenneman – Iowa State University
  37. 37. VENT DOOR WITH AIR CYLINDER Source: Greg Brenneman – Iowa State University
  38. 38. Shading - reduce energy absorbed a. Shade curtain  Fabric over top of greenhouse/tunnel  Degree of shading – depends on crop and time of year b. Shading compound  Permanent shade after application  Removed Aug – Sept Source: Greg Brenneman – Iowa State University with modification by Tim Baker TECHNIQUES TO REDUCE TEMPERATURE
  39. 39. REGULAR SEASON TEMPERATURE TRENDS6
  40. 40. GEOTHERMAL COOLING AND HEATING  Pipes run underground  Air drawn through pipes by blower  Ground is cool in summer, therefore cool air comes out  Hot air drawn in during summer also warms up ground  In winter, the air is warmed by the soil
  41. 41. ACTIVE HEATING  Portable heating units
  42. 42. •50-90% RH generally •Plants, wet soils and floors provide humidity. •Mostly worry about disease promotion. •Vent or heat or both if condensation lingers past mid-morning. Humidity Control Source: Greg Brenneman – Iowa State University
  43. 43. Keep The Air Moving Source: Greg Brenneman – Iowa State University
  44. 44. GOOD AIR CIRCULATION IS CRITICAL Source: Greg Brenneman – Iowa State University
  45. 45. CENTER DUCT FOR CIRCULATION Source: Greg Brenneman – Iowa State University
  46. 46. AIR CIRCULATION DUCT WITH HYDRAULIC MOTOR Source: Greg Brenneman – Iowa State University
  47. 47. CULTURAL PRACTICES TO IMPROVE AIR CIRCULATION  Stake and weave system6
  48. 48. CULTURAL PRACTICES TO IMPROVE AIR CIRCULATION  Pruning
  49. 49. REFERENCES 1. Bartok, John W. et al. Production of Vegetables, Strawberries and Cut Flowers Using Plasticulture. NRAES-133. Natural Resource, Agriculture and Engineering Service. 2004. 2. Byczynski, Lynn. The Hoophouse Handbook, Growing Produce and Flowers in Hoophouses and High Tunnels. Growing for Market. 2006. 3. Demchak, Kathy et al. High Tunnel Raspberries and Blackberries. Cornell University. 2007. 4. www.hightunnels.org 5. Jett, Lewis W. High Tunnel Melon and Watermelon Production. M173. University of Missouri. 2006. 6. Jett, Lewis W. High Tunnel Tomato Production. M170. University of Missouri. 2004.
  50. 50. QUESTIONS & DISCUSSION Patrick Byers Regional Horticulture Specialist 417-881-8909 byerspl@missouri.edu
  51. 51. HIGH TUNNEL INTEGRATED PEST MANAGEMENT
  52. 52. Source: Ted Cary, Lewis Jett, et. al.
  53. 53. TECHNIQUES TO REDUCE TEMPERATURE Evaporation of Water - Needs relatively dry air - Foggers  Requires fine nozzles, high pressure, and clean water - Evaporative Pads  Require mechanical ventilation  Approximately 1 gal/min. of evaporating water will cool a 30’x150’ greenhouse 15o F. with 1 air change/minute Source: Greg Brenneman – Iowa State University with modification by Tim Baker
  54. 54. Source: Ted Cary, Lewis Jett, et. al.
  55. 55. SITE SELECTION AND ENVIRONMENTAL CONTROL  Light  Good sunlight is needed, especially early and late in the season  Calculating the angle of incidence (angle between the sun's rays and line perpendicular to the surface at the point of incidence) at different latitudes is prudent for winter production  Angles of incidence from 0° to 50° have minimal effect on light transmittance  As the angle of incidence increases above 50°, light transmittance decreases rapidly  For example, when the angle of incidence changes from 0° to 90° in 10° increments, the respective transmittance of light through 3mm glass is 0.86, 0.86, 0.86, 0.85, 0.77, 0.65, 0.40, and 0
  56. 56. HOW A PLANT GROWS

×