Developing Apple Trees in the 

 Super Slender Spindle System 



Ronald Perry 



Department of Horticulture, Michigan State University 



The Super Slender Spindle (SSS) system is 

 one of the newest systems to reach North 

 America. It was developed several years ago in 

 Germany and in Holland, where growers 

 wanted to produce the most fi-uit possible and 

 in the shortest time period following planting 

 on small land holdings. Argument still lingers 

 as to its specific origin. Most attribute its steirt 

 on the German side of Lake Constance, where 

 several growers working with Fleuren Nursery 

 in Holland began planting trees on top of the 

 soil (known then as the Bodenzee system) at a 

 spacing of one to two feet by eight to ten feet. 

 The purpose then of planting on top of the 

 ground was to use stress to assist in canopy 

 vigor control. Since then, newer plantings have 

 tended towards planting stocks in the soil. 



Initially, low priced lower quality trees were 

 planted in a four- to five-wire vertical trellis, 

 kept to a height of eight to nine feet. Today, 

 most new plantings have incorporated a T brace 

 with two outrigger wires and alternate trees 

 leaned at 15 degrees fi^om vertical to encourage 

 better light penetration. Trees in the SSS typi- 

 cally are planted at 2000 to 5000 trees per acre. 

 One of the primary constraints to this endeavor 

 is the total cost of trees and of trellis materials 

 per acre (Table 1). This is one reason why those 

 who want to try this system should contemplate 

 finding a way to reduce tree cost (or own a bank). 

 Some have reduced tree costs by making their 

 own trees, and other have tried planting "sleep- 

 ing eye" trees {Great Lakes Fruit Growers News, 

 November 1994, p. 63). Also, the trellis system 

 is expensive (Table 1) and must be strong 

 enough to support fully the trees and the crop. 

 There are only a few orchards that have begun 

 trying the SSS, so there is limited experience. 



The oldest trees in North America on this sys- 

 tem can be found in British Columbia, where 

 there are four- to six-year-old orchards. 



The greatest challenge to the grower is in 

 avoiding shading problems caused by inad- 

 equate vigor control, especially after the fourth 

 year. Trees are not pruned during the dormant 

 season and more time is spent summer prun- 

 ing to control canopy growth. Additionally, some 

 experienced growers are experimenting with ap- 

 plications of ethephon and NAA to aid in growth 

 regulation. Growers are being taught by Euro- 

 pean consultants to rip, tear, or break branches 

 with their hands for summer pruning rather 

 than using shears. Apparently, the wounding 

 stresses branches and decelerates growth. This 

 process is very quick, where vigorous upright 

 growth is torn off. 



This system is very challenging and less for- 

 giving for the grower then other systems. Much 

 time and labor is spent on vigor control and the 

 system is likely not to exceed a life of 10 years. 

 It has the advantage of producing large quanti- 

 ties of fruit in the early years. Remember that 

 production in the first six to seven years in these 

 high density systems is directly related to the 

 number of trees planted per acre. We estab- 

 lished a small row of Bodenzee trees in 1992 

 (1.5' x 14') of Smoothee Golden Delicious on 

 various M.9-style stocks and found cropping per 

 tree in the third year to be slightly less than for 

 trees on the same stocks in the HYTEC {Great 

 Lakes Fruit Growers News, May 1995, p. 25). 

 If we had planted a full acre of these trees on 

 M.9 NAKB T337 (12 pounds in 1994) at a 1.5' x 

 10' spacing, we might have reached production 

 at 830 bushels. Many of these trees had three 

 to five pounds of finiit per tree in the second sea- 



4 



Fruit Notes, Summer, 1995 



