Growing Hops - In the Home Garden

by Susan M. Hiller, Gale A. Gingrich and Alfred Haunold

http://www.oda.state.or.us/hop/ohc.html

The Plant

The hop plant Humulus lupulus L. is an herbaceous perennial, producing annual vines from an overwintering rootstock. In the spring and early summer, vines grow rapidly, winding around their support in a clockwise direction and clinging with strong, hooked hairs. They reach their ultimate height of 15-25 feet by the end of June when, in response to shortening daylength, vines stop growing vertically and produce sidearms which bear the flowers. The hop is dioecious, having separate male and female plants. Only the females produce the cone-shaped "hops" used in brewing.

The male plant serves only as a pollenizer, but is not essential for the female plants to produce hop cones. Hops are heterogeneous and new plants coming from seed could be either male or female.

The rootstock is an underground structure consisting of both rhizomes (with buds) and true roots (without buds) which may penetrate the soil to a depth of 15 feet or more. During the first year little growth and few flowers are produced because the plant is establishing its root system. A normal crop of hops should be expected the second year.

Climate

The hop plant produces best under specific climatic and soil conditions. A minimum of 120 frost free days are needed for flowering. Direct sunlight and long daylength (15 hours or more) is also needed. As a consequence of daylength and season length, hop production is limited to latitudes between 35 and 55 degrees. The hop plant requires ample moisture in the spring followed by warm summer weather. In dry climates the hop plant will produce best if supplemental irrigation is provided.

Soil and Plant Nutrition

A deep well drained, sandy loam soil is best. Soils with a pH of 6 to 7.5 is ideal for hop production. Poorly drained, strongly alkaline or saline soils should be avoided. Fertilizers rich in potassium, phosphate, and nitrogen should be applied each spring. Nitrogen is required at a rate of approximately 150 lbs per acre (3 lbs N/1000 ft²). The nitrogen may be applied in split applications 2 or 3 times between March and mid-July. If manure or compost is applied around the hop plant, fertilizer applications may be reduced accordingly.

Planting

The soil should be tilled to create a weed free area. A strong support system is needed for the plant to climb on. Look for space along fences, garage, or property lines. Plant in early spring once the threat of frost is gone but no later than May. The soil should be worked into a fine, mellow condition prior to planting. In cold climates you can plant rhizomes in pots and transplant in June. If planting is delayed, keep rhizomes refrigerated in a plastic bag to prevent them from drying. Plant two rhizomes per hill with the buds pointed up and cover with 1 inch of loose soil. Hills should be spaced at least 3 feet apart if the hills are of the same variety and 5 feet apart if they are different. The first year the hop plant requires frequent light waterings.

Pruning

When the young vines are about 1 foot long, two to six vigorous vines are selected for each hill and the rest are removed. One to three vines are trained clockwise on a string which has been staked to the hill. Hops mainly grow vertically, but lateral sidearms extend from the main vine and produce flowers. The main concern is to support the vines and prevent the sidearms from tangling. Most cones are produced on the upper part of the plant.

In July, the lowest four feet of foliage and lateral branches can be removed to aid in air circulation and reduce disease development. The removal of lower leaves (stripping) must be done carefully to avoid breaking or kinking the main stem. In August allow additional bottom growth to remain to promote hardiness of the crown and plant vigor for next year.

At the end of the season you can bury healthy bottom vines for propagating new plants the next spring. Simply bury the vines in a shallow trench and mark their location. In spring dig them up and cut them into pieces about 4 inches long. Make sure each new cutting has an eye or bud.