Establishing a Hop Yard...

Trellis Structure 

Building trellis and planting rootstock requires a significant investment. Trellis is suspended over the yard by approximately 135 poles per hectare (55 poles per acre) and connected by high quality wire and cabling that stands five to six meters (16-19.5 ft.) above the ground. Historically, the U.S. hop industry used a 7-ft. x 7-ft. (approximately 2 x 2 m.) spacing, which resulted in 1778 strings per acre.

There were two work rows every 14-ft. Growers typically cultivated a field in two directions with four tractor passes total, two in each direction. In the early 1980's growers began to change to a 3.5-ft. x 14-ft. spacing. This resulted in one work row instead of two. By doing this, growers reduced their tractor work, and the associated expenses, by 75% because they only had to make one pass down the length of the field. Since the plants in the new layout were so close together, it was no longer possible to take the tractor across the rows.  In addition, conversion of hop irrigation systems to drip technology was more affordable, as this spacing required only half the amount of drip tubing than the conventional 7 ft. row spacing.  The number of strings per acre remained the same (1778 strings/acre).

The Hop Plant 

Hops (humulus lupulus) are perennial plants whose rootstock will produce for many years. Some American hop varieties are still commercially viable after 50 years. In the quest for more efficient production, commercial hop fields are generally replanted with clean , high quality rootstock approximately every ten years. Alpha varieties are often removed and replaced with higher yielding super-alpha varieties. These practices preserve optimal yields and enable more efficient production. Hop plants are either male or female, producing annual climbing stems from a perennial crown and rootstock. The stem grows in a clockwise direction around its support (as it follows the sun) and may reach a total height of 25 feet or more in a single growing season. The stem dies back to the crown after the hop cones mature.

The commercial hop is a female plant with flowers that appear as burrs on the side arms which develop along the stem. Each burr eventually develops into a hop cone. Male plants do not produce hop cones, only pollen which causes seeds to be produced in the cones. Hops are vegetatively propagated, with new yards established by planting rhizomes, or potted plants started in a greenhouse from softwood cuttings.

The mature hop cone contains numerous oil glands (lupulin glands), appearing as a yellow pollen-like substance inside the cone. The individual lupulin gland is a yellow resin gland containing the important brewing constituents of alpha acids, beta acids, and essential oils. The amounts and percentages of total composition of these compounds varies between varieties.