Growing Peaches, Pears, Cherries and Strawberries in an Unheated High Tunnel

This project involves planting peach, pear, sweet cherry, and sour cherry trees in an unheated 30x48 foot high tunnel.  Strawberries are planted along the outer edges where the tunnel is too low for trees to grow.  Similar trees are planted outside for use as a control. 
                
The high tunnel was ordered and erected in the spring of 2014.  The fruit trees were planted, staked, labeled, and tree wraps applied in June 2014.  Strawberries were also planted in June 2014.  Soaker hoses were laid by the trees and strawberries.  Irrometers were installed along each row of fruit trees.  Landscape fabric is installed between the tree rows and along the ends.  Trees ordered for the project are all hardy to zones 4 or 5 and are either dwarf or semi-dwarf.  The trees included in this project are as follows:

   PEACH TREES:  Burbank July Elberta Peach Dwarf Supreme
                          Starking Delicious Peach Dwarf Supreme
                          Stark Elberta Queen Peach Dwarf Supreme
                          Stark Early White Giant Peach Dwarf Supreme
                          Reliance Peach Dwarf Supreme
   PEAR TREES:  Moonglow Pear Dwarf
                        Starking Delicious Pear Dwarf
                        Stark Honeysweet Pear Dwarf
   SWEET CHERRY TREES:  Emperor Francis Sweet Cherry Semi-dwarf Supreme
                                       Starkrimson Sweet Cherry Dwarf Supreme
   SOUR CHERRY TREES:  English Morello Cherry Dwarf
                                     Montmorency Cherry Dwarf

During the summer of 2014 there were 8 trees that did not grow - 2 Sweet Cherry Starkrimson, 2 Peach Early White Giant, 3 Peach Starking Delicious, and 1 Pear Moonglow.  The winter of 2014-15 took a huge toll on the fruit trees.  The 2 sour cherry trees were the only trees to survive in the outside control group. The results in the high tunnel were as follows: 
 
   PEACH TREES:  Early Elberta Queen Peach - all 4 winterkilled
                          July Elberta Peach - all 4 winterkilled
                          Early White Giant Peach - 2 never grew and 2 winterkilled
                          Relaince Peach - 3 winterkilled and 1 survived
                          Starking Delicious Peach - 2 never grew and 2 winterkilled
   PEAR TREES:  Honeysweet Pear - all 4 survived
                        Moonglow Pear - 3 winterkilled and 1 survived
                        Starking Delicious Pear - all 4 winterkilled
   SWEET CHERRY TREES:  Emperor Francis - all 4 winterkilled
                                       Starkrimson - 2 never grew and 2 winterkilled
   SOUR CHERRY TREES:  English Morello - all 4 survived
                                      Montmorency - all 4 survived

Replacement trees were ordered for all the trees that did not survive in the high tunnel. The fruit trees had a one year guarantee so they were replaced free of charge. All the dead trees in the high tunnel were dug up and the replacement trees were planted in May 2015.  Trunk diameter was measured and recorded for each tree on June 21, 2015 and again on October 14, 2015.  The average increase of trunk diameter for trees in the high tunnel is shown below:

   PEACH TREES:  Early Elberta Queen - 4 replants - .146
                          July Elberta - 4 replants (2 never grew) - .106
                          Early White Giant - 4 replants(1 never grew) .105
                          Reliance - survivor - .474
                          Reliance - 3 replants - .136
                          Starking Delicious - 4 replants - .077
   PEAR TREES:  Honeysweet - 4 survivors  - .088
                        Moonglow - survivor - .036
                        Moonglow - 3 replants - .043
                        Starking Delicious - 3 replants(1 never grew) - .017
                        Starking Delicious Pear replanted with Starking Delicious Peach - .040
   SWEET CHERRY TREES:  Emperor Francis - 4 replants(1 never grew) - .103
                                       Starkrimson:  4 replants(2 never grew) - .284
   SOUR CHERRY TREES:  English Morello - 4 survivors - .050
                                     English Morello - 1 outside survivor(Oct 2014 to Oct. 2015) - .415      
                                     Montmorency - 4 survivors - .176
                                     Montmorency - 1 outside survivor(Oct. 2014 to Oct. 2015) - .415

In late winter all the leaves were knocked off the fruit trees and then the trees were pruned.  In mid April the first leaves appeared on the Honeysweet pears and the sour cherry trees started blooming the first week of May.  One of the Honeysweet pear trees produced a single blossom. When measuring trunk diameter on the fruit trees in June spider mites were found on some of the pear trees.  A powder was tried on them, but it didn't do much good.  Then a soap mix was sprayed on the mites and that took care of alot of them.  The soap mix spray was applied 2 more times in July.  The first week of July we figured out the sour cherry trees had Cherry Leaf Spot - it was causing the sour cherry tree leaves and blossoms to fall off.  The trees were sprayed with a fungicide and that stopped the leaves from dropping off, but all the blossoms were lost so no fruit from the high tunnel trees.  6 sour cherries were harvested from the 2 control trees outside - all smaller than my fingernail.  

Evie II strawberries were planted along both side walls of the high tunnel in May 2014.  Most of the strawberries on the west wall came back in the spring of 2015 so they were left to grow and produced berries all summer and fall - last picking was in the first week of November.  The strawberries along the east wall all died out during the 2014-15 winter so they were replanted with June bearing strawberries from beds we had elsewhere in the garden.  Our strawberries in the garden did poorly so the strawberries in the high tunnel produced enough for our own use this summer, but not enough to sell.  

Bird netting was installed along the side walls in April 2015 so the sides could be left open for better air flow.  This helped with the mold problem we had on the strawberries last summer. 
There was a garter snake in the high tunnel throughout the spring and early summer that kept the cricket problem under control.

The soaker hoses were left in the high tunnel over winter.  The irrometers were pulled last fall when it got down to freezing at night and reinstalled this spring when we were ready to start irrigating again.  They were pulled again this fall when it started freezing and will be reinstalled in the spring 

The winter of 2014-15 we kept the high tunnel closed up.  After losing the majority of our fruiit trees during the winter further study was done of the weather records.  The conclusion was drawn that there was too much temperature flucuation inside with the tunnel closed up.  Following is an example of temperatures for one week in Feb., 2014:

              INSIDE HIGH TUNNEL                                OUTSIDE HIGH TUNNEL
  DAY          HIGH      LOW                                          HIGH        LOW
   16            54.2       0.1                                            16.4         -14.2
   17            42.3     -10.3                                            0.2          -18.0
   18            44.9     -17.2                                           -2.4          -27.5
   19            47.9     -15.3                                           18.5         -28.7
   20            53.6      13.1                                           23.3           5.7
   21            51.7     -11.8                                            5.8          -23.4
   22            35.9     -19.5                                           -7.3          -32.9

By the first week of December most of the leaves had dropped so the final cleanup of leaves was done on Dec. 4.  By mid December daytime highs were staying below freezing so on Dec. 13 the sides of the high tunnel were opened up to see if the trees will survive the colder temperatures without the temperature flucuations of last winter when the tunnel was closed up.

A tour of our high tunnels and garden was held on Sept. 28 with 12 people in attendance.  On October 16 we along with other area farmers worked with Dakota College at Bottineau and Dickinson State University on a video they produced.  They had a NIFA grant to produce a recruitment video for the colleges.   Most of the video is on vegetable production, but there are a few shots of the fruit trees and the weather station in the high tunnel.  The video can be viewed at https://youtu.be/KPWXZU5OPol or at https://www.facebook.com/ndveggies.

Following is the average number or years it takes for the trees to start bearing fruit and the average yield that can be expected from the various types of dwarf fruit trees under normal growing conditions: 

    TYPE OF TREE                        STARTS BEARING FRUIT         AVERAGE YIELD
Dwarf Pear Trees                                  4-6 years                        6-8 bushels
Dwarf Peach Trees                                2-4 years                        3-4 bushels
Dwarf Sweet Cherry Trees                     4-7 years                        8-10 gallons
Dwarf Sour Cherry Trees                       3-5 years                        3-5 gallons

• English Morello sour cherry tree – in high tunnel – 4-4-15
• Dead leaves on fruit trees in high tunnel – March 2015
• Leaves knocked off and swept up – 4-4-15
• Honeysweet pear trees in high tunnel – first leaves – 4-14-15
• Honeysweet pear tree with one blossum – 5-5-15
• Cherry leaf spot on English Morello cherry trees – 7-5-15
• Sour cherry trees – outside – 7-5-15
• High tunnel with side walls open for the winter – Dec.2015
• 2 of 7 Evie II strawberries picked in the high tunnel on 7-17-2015
• English Morello sour cherry tree – outside – 4-4-15