high tunnel basics 2009

Basics of High Tunnel Production

Terrance T. Nennich Extension Professor

Vegetable and Small Fruit Production University of Minnesota Extension

[email protected]

© 2009 Regents of the University of Minnesota

High Tunnel Research Sites in Minnesota

Experiment StationsGrower Cooperators


What are High Tunnels

• High tunnels are not a poor persons greenhouse

• High tunnels are a separate intense technology which allows crops to be grown up to three zones earlier and later and eliminate considerable risk.


What are High Tunnels?

• Structures that resemble some greenhouses -in appearances only

• Use no artificial heat (except for emergencies)

• Use no artificial ventilation such as fans, tubes or forced air

• Plants are grown in the ground.

• Many shapes and sizes


What Can be Grown in High Tunnels in Zones 2 and 3.

• Any crop that can normally be grown in the area

• Most crops in zones 4 through 5.

• Some in zone 6 and be on.


Winter Tour


Advantages of High Tunnels

• 4-8 weeks earlier production in the spring• 2-5 weeks later possible production in the fall• Grow crops not usually grown in the area• Very high yield per plant• Crop mix• Very cost effective• Usually no pesticides needed• Organic production


Advantages of High Tunnels

• Natural disease control

• Insect control

• Control water

• Guarantee a crop

• Reduce cull fruit.


Concerns of High Tunnels

• Cost involved

• Education

• Planning

• Management

• Time


Key Components of high Tunnels

• Good well drained raised soil

• Roll Up sides

• 6 mil UV treated plastic

• Can be built from many materials


Why High Tunnels Work

• Lets review the principles of plant growth

Time

Heat

Light

Stress


Time

• All plants need time to advance in growth and mature

• How much growth that occurs in a given length of time depends on how ideal the environmental growth factors are.

• In northern climates heat is the one factor that we need to be concerned about.

• Seed catalogs use maximum conditions in deciding growing days.


Heat

• Plants are classified by there ideal heat requirements.

• Tomatoes , peppers, 80-90 degrees

• Cucumber , melons , 85-95 degrees

• Heat is measured in growing degree days

• Duration of Temperature is Critical


Growing Degree Units

• Normal figure used for warm season crops is 50 low and 86 high

• Growing degree Units =

(high for day+ low for the day) – 50 Divided by 2

(86) (50)


Growing Degree Days units for Tomatoes

• Early to mid-season tomatoes will require 1400 to 1600 GDD to the first ripe fruit.

• Late season varieties will require 2000 to 2200 GDD


Growing degree day samples

Low of 40, high of 60 = 5 GDD





Growing Degree ComparisonInside and Outside Tunnel

• Inside Tunnel

• March 281 GDU

• April 435 GDU

• May 502 GDU

• June 570 GDU

• July 624 GDU

• Aug 544 GDU

• Sept 570 GDU

• Oct 303 GDU

• Outside Tunnel

• March 5 GDU

• April 99 GDU

• May 183 GDU

• June 366 GDU

• July 505 GDU

• Aug 374 GDU

• Sept 396 GDU

• Oct 101 GDU


Growing Degree Days units for Tomatoes

• Early to mid-season tomatoes will require 1400 to 1600 GDD to the first ripe fruit.

• Late season varieties will require 2000 to 2200 GDD


High Tunnel Planting DatesNorthern Minnesota

• Onions , radishes, lettuce Mar 25-Apr 7

• Cabbage, broccoli etc. Apr 7-15

• Tomatoes, peppers April 25 - May 10


Different Locations in the state

• March 31

• Bemidji Minnesota high 45 Low 20

• Austin Minnesota high 47 Low 28


January 2006


Production Data

• Tomatoes : first harvest in tunnel July 18

• First harvest outside Aug.11

• Yield 10-25+ per plant

• Cucumbers: first harvest June 16

• Yield per plant 30-35 pounds


Common Mistakes Beginning Growers Make

• Tunnels get to hot >130+

• Don’t shut roll up sides early enough in the evening-loose growing degree units

5 GDU a day for a month = 5-8 day

• Weed Control inside and out

• Monitor the water uptake

• Punning and trellising


Tunnel Direction

• Narrow end against prevailing high winds

• The outside air direction has little to do with the cooling of the tunnel

• Recommend tunnel construction for 100 MPH winds


Yield Potential & Nutrient Needs

• Yields in a high tunnel can be 3 to 4 times the yield obtained in the field

• Higher yields will required more nutrients, but knowing how much to apply is a challenge– Lack of nutrients – deficiencies

– Excessive nutrients – salt build up

– Both situations affect yield and quality


Cucumber Results

CucumbersAll the fruit from all 26 cucumber plants were weighed and evaluated for quality. All data is in pounds per plant.

Sweet SuccessFirst Harvest June 8Total Yield/Plant 65.12Culls 8.0MKT/sq/ft 9,52

Total sq/ft 10.85

Total Yield Acre = 472,628 or 236 tons.


Soil Nutrient Research

Sweet Success Cucumbers

0-6 inch soil depth

N P K

Before Season 335 330 1050

After Harvest 12 175 256



Sweet Success Cucumbers6-12 inch soil depth

N P KBefore Season 100 150 580



Tomato Results

Variety First harvest Total yield Culls Marketable sq/ft Total sq/ft

Cobra June 28 37.0 4.0 3.89 4.63

Sunshine June 24 16.5 5.1 1.90 2.75

Mt. Spring July 11 18.5 4.2 2.38 3.08



Cobra Tomatoes6-12 inch soil depth





Cobra Tomatoes12-24 inch soil depth





Cobra Tomatoes

0-6 inch soil depth

N P K

Before Season 335 330 1050



Berry quality


High Tunnel Roof Vent


Solar Heating of the Soil

• Cucumbers – May 15

• Tomatoes – June 5


Local High Tunnel List Serve

• Be sure to sign up for the Minnesota/North Dakota List Serve.

• Talk to local producers, be informed of upcoming events.


On line at:

www.hightunnels.cfans.umn.edu

Minnesota Fruit and Vegetable Growers Association – (763) 434-0400


http://www.hightunnels.cfans.umn.edu/�

Minnesota High Tunnel Web Site

• http://hightunnels.cfans.umn.edu/


Upcoming Research

• Plant density studies

• Fertility studies

• Variety Studies

• Irrigation Studies

• Raspberries, Perennial crops , Overwintering


Seminars on High Tunnels

• Getting Started with High Tunnels• Crops and Yields• Marketing • Soil Fertility/Nutrient Use• Irrigation• High Tunnel design • Organic Production• Fruit Production


QUESTIONS

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