overwintering garlic in high tunnels

Overwintering Garlic in High Tunnels

Terrance T. NennichExtension Professor

Commercial Fruit and Vegetable ProductionUniversity of Minnesota Extension.

[email protected]

© 2009 Regents of the University of Minnesota

Purpose of the ResearchThe Question??

• With winter temperatures reaching as low as –40 to – 50 F degrees in Zone 2 and 3 and the inside soil of high tunnels receiving no snow protection, would fall planted garlic inside high tunnels survive the winter and produce a good early crop of garlic the next spring?


Research Strategy

• The variety Music Garlic would be planted both inside high tunnels and in outside plots.

• If that was successful we would they try less winter hardy varieties.


Research Location

The location of the research was Bagley Minnesota, about 25 miles west of Bemidji.

Zone 2 – 3


• The garlic research project was conducted over a four year period

– 2005, 2006 ( planted, harvested)

– 2006, 2007

– 2007, 2008

– 2008 , 2009


Variety Selection.

• The variety Music was selected for the first three years of this study.

• For the fourth year a large selection of less winter hardy varieties were selected


Tunnel Design

• Two different high tunnel designs were used in this research project.

– Gothic V roof design

– Small round design.


Planting Dates - Outside

The garlic was planted on the following dates outside of the tunnel

The First Three years

2005 September 21

2006 September 23

2007 September 19

Six inches of straw was applied following planting.


Planting Dates Inside the Tunnels

2005 October 20

2006 October 18

2007 October 22

Six inches of straw was applied 30 day

after planting


Cold Temperature Data

Days below 0 F Coldest Day

2005-06 17 days -37 F

2006-07 24 days -41 F

2007-08 33 days -38 F

The 2006-2007 winter had 8 consecutive

night -20F or colder.


Snow Fall Data

• 2005-2006 Ample but below average

• 2006- 2007 Little snow cover

• 2007- 2008 Average snow cover


Survival Rate (%) Inside TunnelGothic

• 2005 – 06 94%

• 2006-2007 92%

• 2007-2008 95%


Survival Rate (%) Inside Tunnel Round

• 2005 – 2006 92%

• 2006 – 2007 87%

• 2007 – 2008 94%


Survival Rate Outside Tunnel

• 2005 – 06 69%

• 2006 – 07 2%

• 2007 – 08 79%


Harvest Data

• Average 3 year harvest was 21 -30 days earlier in high tunnels.


Size Difference

• The size of the garlic grown in the high tunnels was about 30% more then outside.

– Hard to statically compare because of different soils, fertility, rainfall, ect.


Results

• The effect of extreme cold winter temperatures of the variety Music Garlic grown in high tunnels in zone 2 or 3 has little effect on garlic winter survival.

• The garlic grown in high tunnels had a much higher survival rate and increased size then the garlic grown outside. Drastic differences were noted in 2006 -07 when there was very little snow cover outside.


2008-2009 Research

• In the fall of 2008, 15 different varieties, many soft neck were planted in the high tunnel for a winter survival study


Research Strategy

• 20 cloves from 15 different varieties were planted in a Gothic high tunnel on October 20, 2008 to be harvested spring 2009

• Cloves were covered with straw at a 6 inch depth.

• Drip tape was placed in the high tunnel before planting


Significant Weather Data

• In 2009 there were two nights that that temperatures dropped near or below

-50 F


Garlic Varieties Used

• Music• Russian Silverskin• Asian Tempest• Moroccan Silverskin• Blossem• Moroccan Hardneck• Chesnok Red• Japanese


Garlic Varieties

• Creole Red

• Inchellium Red

• Silver White

• Burgandy

• Montana Giant

• Spanish Red

• Chinese


Results

• All varieties had over a 85% survival rate.

• The following slides picture the varieties


Future Research

• Given this data, how will other perennial

plants overwinter in high tunnels????


Questions


overwintering garlic in high tunnels

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