Moving toward high density apple systems: Pruning and training demonstration on March 20

Why growers should be moving towards high density systems, and a hands-on demonstration in northwest Michigan for pruning and training tall spindle systems.

Many Michigan growers are moving toward planting high density apple orchards as these types of systems have been shown to maximize profitability through early yield and improved fruit quality. Dwarfing rootstocks and improved cultivars have hastened high density plantings across the United States. Research from Cornell University (T. Robinson, S. Hoying, and A. Demaree) has shown that the most profitable system to be the tall spindle system, which many growers have adopted this system in Michigan.

There are many components of these modern apple planting systems. First, trees are planted at a much higher density than our traditional orchards or even orchards planted to the vertical axe system. In most tall spindle plantings, there are 1,000 to 1,300 trees per acre. Michigan growers should be aware of their soil type before selecting the rootstock; sandy soils will require a more vigorous rootstock to fill space in these high density systems, while heavy soil can tolerate rootstocks with less vigor. These dwarfing rootstocks have really been the key to high density orchards, and there are many fully dwarfing rootstocks available, including the new Geneva series from Cornell University that has fireblight tolerance.

Because growers are readily adopting these new systems, nurseries have responded to the grower need to plant highly feathered trees. We recommend that trees planted to the tall spindle system have 10 to 15 feathers per tree. Properly feathered trees will result in early bearing, which is essential in these new systems as it offsets the increased costs for higher tree numbers and trellis systems. Tall spindle orchards must have a support system, and there are many variations of current support systems that will be effective for Michigan orchards.

Despite that Michigan receives adequate rainfall in most years, irrigation is highly recommended for a tall spindle system. The main reason for growers to move to a tall spindle system is early fruiting, hence grower returns. In fact, trees must fruit in the second or third leaf to keep low tree vigor and, more importantly, to provide income from earlier fruit sales than traditional plantings. For more information on tall spindle systems, please refer to the MSU Extension News article “Why consider planting a tall spindle system?

For those growers that have planted apple high density systems or are intending to do so in the future, we are hosting a pruning and training workshop on March 20 in northwest Michigan. MSU Extension’s Phil Schwallier will provide his expertise in pruning tall spindle systems. Schwallier is an expert in dwarfing apple rootstocks, high density systems, and apple pruning and training. He will be on hand from 1-5:30 p.m. at three orchards in Michigan’s Benzie and Manistee counties where we will prune trees of different ages and on different rootstocks.

The tour will begin at Blaine Christian Church, 7018 Putney Road, Arcadia, Mich., (see map) at 12:30 p.m. to carpool to our first stop. We will head to Bill Lentz’s farm on Eden Hill Road and expect to be at the farm at 1 p.m. This stop will include pruning 3- and 4-year old SweeTango trees that are planted 4 feet by 12 feed on Bud 9, m26, and V1.

The tour will travel next to Dave Smeltzer’s West Wind Orchards on the corner of M-22 and 13-mile Road. Here Schwallier will lead us in pruning 6-year old Gala trees on m26 and 3- and 4-year old LindaMacs and Pioneer Macs on 118; we will be at Smeltzer’s orchards from 2:40-3:40 p.m. Refreshments will be available at the West Wind Orchards.

The third stop will be at Evans Brothers Farm from 4:00-4:40 p.m. on Taylor Road where we will focus on 3-, 4-, and 5-year old SweeTango that are planted 3.5 feet by 13 feet on Nic29. We will also look at high density 1-year old Jonagold trees. Although we will spend some time pruning SweeTango trees, the same concepts apply to other varieties planted to a high density system. The last stop will be at Putney Orchards from 5-5:30 p.m. up behind the church.

The cost of the tour is $25. At the conclusion of the tour, the Benzie-Manistee Horticultural Society annual dinner will take place at the Blaine Christian Church at 6 p.m. Calvin Lutz III and Jared Lutz will give a presentation on their recent trip to agricultural areas of New Zealand. The cost of the dinner is $15.

Please call the Northwest Michigan Horticultural Research Station for more information at 231-946-1510.

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