Optimizing a Short Trellis System for Growing Cascade Hops in Michigan

Planting Layout:

We planted 400 new Cascade hops plants for the study in spring of the study's year 1 (of 2).  Six rows were rototilled 5 ft. wide and 100 yds. long.  Spacing between rows and between plants was varied as follows, to evaluate the effect of spacings:

-          Rows #2 and #3 employed 10 ft. spacing between rows, where Row #2 utilized 36 in. spacing between plants and row #3 42 in.

-          Rows #5 and #6 employed 8 ft. spacing between rows, where Row #5 utilized 42 in. spacing between plants and row #6 36 in.

-          Rows #1 and #4 serve as control rows with varied spacings.

Mixed ryegrass and red clover were planted as cover crops between rows.  Straw bales were spread for mulch each winter. 

In spring of year 1, soil analysis was performed and nitrogen/phosphorus/potassium fertilizer added at recommended rates.  Sulphur was broadcast to lower pH which began around 7.0. Following these initial applications, fully organic methods were followed, and only composted horse manure was added for nitrogen later in year 1 and throughout year 2.

Trellis design:

14 ft. black locust poles, for longevity and organic compliance, were sunk every 42 ft. along five of the rows.  (The remaining row--#5--was between rows with posts but had none of its own.)   3 ft. deep holes were dug with a towable auger and a mixture of gravel and lime dust placed at the bottom of the holes for drainage.  All poles on the outer perimeter were angled outward about 20 degrees to align loading with the post axis, and then they were secured to 48” ground anchors with turnbuckles for future tension adjustment.  The ground anchors were spun in manually with a crowbar.

A low height, hi-tension wire was placed 18” from the ground down each row to tie twine to by each plant and to support drip irrigation.   The extra row without posts utilized short stakes instead (2’ above ground) to support a low wire.

5/16” 7x19 galvanized cable was strung through eye hooks in the poles (laterally/across the rows).  3/16” 7x19 galvanized cable was strung along the rows, over the lateral cables, and secured to eye hooks at the ends with two cable clamps each.  The 3/16” cable was also used for guy wires to the anchors (one at each side pole and two at each corner pole).  Galvanized cable thimbles were used at abrupt turns in the cable (for example when reversing direction through the eye hook or at the perpendicular end wire) in order to minimize cable stress points.

Plastic tie straps were tied at the intersections of cables (lateral to longitudinal) to prevent side-to-side motion between the cables while allowing longitudinal motion which occurs as the bines grow and the weight distribution varies.  Wires were accessed from a 6’ ladder and from the back of a UTV.  Cables were unrolled by supporting the cable spool from the bucket of our tractor loader with binder chains. 

Irrigation design:

Residential water was used for low initial cost and expediency.  A timer valve was attached to a house spigot.  1” poly tubing runs 550’ to the hop field.  A fertigation tank is mounted in parallel.  The poly tubing also serves as a header for seven T-valves, one per plant row, that feed ½” pressure compensated drip lines (for even output despite length or slope) with ½ gph emitters.

Plant Care:

Weeding was the greatest challenge.  To avoid non-organic herbicides, we relied on labor intensive manual weeding from May through August, either pulling individually or using a weed trimmer.  The weed trimmer was much more efficient but care must be taken not to damage bines.  We used a brush hog to maintain the ryegrass cover between rows and around the perimeter every other week. 

Bines were trained each May, selecting 2 or 3 of the healthiest shoots. 

From June, we watered 2 gallons once every 3 days (alternating rows), except when it rained.  We also began weekly "scouting" for pests and disease:  predominately leaf hoppers, Japanese beetles, spider mites, powdery mildew, and downey mildew.

We applied composted horse manure (produced following the Berkley method of manually turning the pile every other day for 3 weeks) the first week of April and July and once more in October, after the harvest.  We applied an estimated 2 tons each time, to approximate a rate of 200 lbs. nitrogen per acre (over our half acre) assuming 0.8% nitrogen content of the horse compost.

One string of sisal twine was also hung at each plant (using clove hitch knots) and the bines that had reached the low wire were trained the same first week of July.

In the second year, we experimented with trimming the apical meristems as the plants reached the top wire to promote side growth, leaving some sections untrimmed for comparison.

Harvesting was conducted manually the first week of September in year 1.  The hops were dried and pressed into 2 oz. hop plugs with a hand-made rig (filling a 1.5" diameter PVC tube, and compressing with pipe clamps).  In year 2, bines were cut down and taken to a harvester for processing and later dried and pelletized.

Fall cleanup consisted of removing bines (which may otherwise spread disease), mowing, and spraying Neem oil for organic mildew control.