Growing Hops - In the Home Garden
Susan M. Hiller, Gale A. Gingrich and Alfred Haunold¹
*This version of their fact sheet has additions and edits by Steve Miller for New York conditions.
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 day length, vines stop growing vertically and produce side arms 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 pollinator, 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.
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 day length (15 hours or more) is also needed. As a consequence of day length 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. A soil with a pH of 6 to 7.0 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) for mature plants, half that the first year or two. 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.
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 and can be planted into June in NY. Rhizomes can go in a little earlier because they are underground. 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 watering. Mature plants will benefit from a seep hose and regular watering if rainfall is sparse. Hops need plenty of water but should not be water logged.
When the young bines are about 1 foot long, two to six vigorous bines are selected for each hill and the rest are removed. One to three bines are trained clockwise on a string which has been staked to the hill. Be very careful not to damage the growing point of the bine as this will affect the production of the hop flowers. Hops mainly grow vertically, but lateral sidearms extend from the main bine and produce flowers. The main concern is to support the bines and prevent the sidearms from tangling. Most cones are produced on the upper part of the plant.
In early July, the lowest four feet of foliage and lateral branches can be removed on mature plants 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.
This disease is caused by the fungus Pseudoperonospora humuli. The fungus infects only the hop plant and will not affect other garden plants. The disease first appears in the spring as infected shoots (spikes) emerge from the overwintering rootstock. The number of infected shoots may vary from none to all in any given hill. Infected shoots are stunted, brittle, and lighter in color than healthy shoots. The leaves are often deformed and curled. Infected shoots are unable to climb. Gray or black masses of fungal spores are often present on the underside of infected leaves. Spores are dispersed by wind and rain. The disease is favored by warm (65-70°F) wet weather and the fungus requires free water on leaf and shoot surfaces for infection. Spiked shoots should be removed promptly and buried.
Flowers often become infected when blooming occurs during wet weather. Young cones that are infected stop growing and turn brown. When older cones are attacked, part or all of the petals turn brown and cones fail to develop properly.
This disease is uncommon in the Pacific Northwest but may occur in the East. Symptoms include yellow veining of the leaves and wilting of leaves and vines. Early symptoms may include wilting on only one side of a leaf. A brown discoloration inside the vine may be observed by cutting diagonally into the vine. Depending on the hop variety and the strain of the fungus, disease can vary from year to year. A plant showing symptoms this year may seem entirely healthy the next year. There are no effective control measures. The fungus can persist in the soil for several years. If this disease recurs regularly, remove the infected plant and replace with a new one in a different location
Hop plants are extremely sensitive to soil residues of the pesticides heptachlor and chlordane. Chlordane was widely used in home gardens in the l960's but both were banned in 1972. Symptoms of heptachlor and chlordane poisoning may be similar to those of Verticillium wilt but there are some important differences. The lower part of the affected vine will have a rough, scaly appearance with deep cracks which may ooze sap. Vines are brittle and may easily snap when bent. In cross-section, the central sap of the vine may have a darkened, water-soaked appearance instead of a light color. Plants will likely exhibit a slow decline over a period of 2-3 years. There is no known cure. The hop varieties Cluster and Chinook seem to be somewhat more tolerant than other varieties.
Symptoms of virus infection vary with environmental conditions. The virus may cause leaf and vine tip distortions, tip die back, yellow spotting of the leaves, stunted growth, failure to climb on the trellis and flower blasting. There is no cure and severely affected plants should be removed and destroyed. Over the years many of the most severe viruses have been eradicated from commercial production. Rootstock purchased from a reliable propagator is unlikely to have severe virus problems.
Hop aphids and spider mites are the most common hop pests. Other less serious insect pests include wire-worms, leaf rollers, armyworms, hop looper, root weevils, omnivorous leaftiers, western spotted cucumber beetles, corn earworms, and several species of cutworm. These usually are not present in damaging numbers.
Hop aphid, Phorodon humuli
The hop aphid is a small (2mm) soft bodied, pale green pest. The hop aphid overwinters on Prunus species (ie. ornamental plum trees) and in the spring return to the hop plant. Hop aphid infestations develop more rapidly during cool weather. The hop aphid does damage by sucking plant juices. Aphids should be controlled before or during flowering to keep them from entering the young cones. Once the aphids have entered the cones, they will secrete a honeydew and cause a sooty mold in the cones.
Spider Mites, Tetranychus urticae.
The adults are very small, have eight legs. They are pale green, yellowish to reddish in color, often with a dark spot on each side of their body. A hand lens is needed to see the pearly white spherical shaped eggs. The spider mite feeds by puncturing the lower leaf surfaces and withdrawing plant sap. Each puncture produces a small light colored spot. Eventually the leaves become bronzed, shrivel and die. White webs may also appear if infestation is severe. The spider mite will also feed on the petals of the cones causing them to turn brown, a condition growers call "red hops". Spider mites are a problem during prolonged periods of warm, dry weather. Mite predators include the western predator mite and the small black lady beetle. Regular washing of the plant's leaves with your garden hose may prevent an outbreak.
Cutworms over-winter as larvae or pupae in the soil. The adult moths emerge in late spring and lay eggs. The larvae that emerge from the eggs feed on plant stems at night. Cutworms can generally be found just beneath the soil surface during the day.
Eastern comma, Japanese beetles, black vine weevil and potato leaf hopper are all potential insect pests on hops in New York.
On a small scale hops can be mulched and hand weeded to keep down weed growth. Hops are sensitive to herbicides like glyphosate and 2, 4 D so be careful not to let these drift onto the hop leaves or stems.
Hop harvest in the Pacific Northwest and in New York usually runs from mid August to mid September, depending upon the variety. If you want to use your hops for ornamental purposes, pick your hops early. Otherwise hand pick hop cones and dry them in a food dehydrator.
To determine ripeness pick a cone and touch and smell. If the cone is too green it feels slightly damp to the touch and has a softness to its scales. If you squeeze the cone it will stay compressed in your hand. A dry cone will feel papery and light. It will feel drier than a green cone, some varieties take a lighter tone as they mature. If your hands quickly take up the smell and are slightly sticky due to the yellow powdery lupulin, your hops are ready for harvest.
To harvest, the cones can be hand- picked in the field. This process takes about 45 minutes to an hour /mature plant. Picking in the field will preserve the full amount of nutrition in the plant for over wintering. If you have many plants you may want to cut the vine at the bottom leaving 3-4 feet of the vine to lay on the ground and cut the string at the top. Lay the vine on the ground and pick off the cones. This can be done in the shade, just as they did in the old days. The harvested vine can be mulched, chipped up, or woven into a wreath. When handling fresh hop plants wear long sleeves and gloves because the hooked hairs of the plant may cause a slight rash. Hops are high in natural estrogen and some precaution may be necessary for pregnant women such as wearing gloves.
If you choose to construct a dryer, good airflow is essential, and the temperature must not exceed 140°F. Drying hops at a lower temperature takes longer, but a better quality hop is obtained. For drying the low-tech way, you can use a window screen. Spread the hops evenly across the clean screen. Place the screen off the ground and in an enclosed area to keep wind and bugs from creating problems. A healthy vine will produce 1-2.5 pounds of dried cones per plant.
The dried hops are ready for storage when springy to the touch and the yellow lupulin powder easily falls out. Another indicator is when the central stem breaks rather than bends. The stem takes much longer to dry than the petals. The enemies of hop quality are moisture, sunlight, oxygen and heat. So keep them cold, dry, in compressed bags and in the dark. Cones are best stored in plastic bags that can be sealed. It is important to make sure the cones are sufficiently dry. If cones are not properly dried, they become moldy, wilted, or even rancid and cannot be used for brewing. Fill the bag until the cones are well compressed. Once the bags have been sealed and properly labeled store them in a freezer. Thawing and refreezing stored hops reduces quality and freshness.
¹Administrator, Oregon Hop Commission, Salem, OR; Extension Agent, Oregon State University, Salem, OR; and USDA, Hop Research Geneticist, Oregon State University, Corvallis, OR, respectively. EXT/CRS 104 July, 1995
*Steve Miller is Cornell Cooperative Extension’s Hops Specialist. More information may be obtained by visiting the Northeast Hop Alliance website at www.northeasthopalliance.org
Last updated October 20, 2015