The hop (Humulus Lupulus) is a hardy, perennial plant which produces annual vines from a permanent root stock (crown). Vines may grow up to 25 feet in a single season but will die back to the crown each fall. In addition to the true roots and aerial vine, the crown also produces underground stems called rhizomes. Rhizomes resemble roots but possess numerous buds and are used for vegetative propagation. Thus propagated, all plants of a given variety are genetically identical.
Hops are dioecious, which means they have separate male and female plants. Only the female produces the flowers that are used for brewing or medicinal purposes. Male plants have no commercial value, but are used to pollinate females. Pollination stimulates higher yields by increasing cone size and seed set, but because brewers prefer seedless hops, males are only grown with other wise poor yielding female varieties. Hop seed from a pollinated female is only planted when a cross between the male and female is desired to obtain a new variety.
Hops are native to the temperate zones of the northern hemisphere. They are found wild in western Europe, Asia and certain parts of North America. Commercial hops are generally grown between the 30th and 50th parallel north or south latitude and at various altitudes. Therefore the ability to grow hops is usually not limited by your location on earth. The health of the vine is more dependent on the growers ability to provide proper growing conditions and care. Under good conditions, hops are a prolific vine, will produce from 1/2 - 2 pounds of dried flowers per plant, and will be a joy to grow and utilize.
|Upon obtaining the rhizomes,
they should be stored in a plastic bag slightly moistened and kept in a
refrigerator until you are ready to plant.
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, friable condition prior to planting. In cold climates you can plant rhizomes in pots and transplant in June.
Plant 1 rhizome 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.
In this discussion of hops, I will be referring to the female of the species. Being a perennial, the hop lays dormant during winter and is rather unaffected by freezing temperatures. The time of year when the annual vines break ground, when they flower and when they die back is very much determined by local temperature and day length. The vines will not break ground until soil temperatures have risen to the point where most spring flowers appear. A minimum of 120 frost free days are required for the hop to fully ripen a crop of flowers. Once out of the ground the vines need to be supported off of the ground. Vegetative growth continues until approximately mid-July when most hops are either past bloom or in full bloom depending up on location and variety.
At this "burr" stage the flower is approximately 1/4 inch in diameter and is composed of many florets whose styles give it a spiny appearance. This is when the flower is receptive to pollen and if males are present, wind-borne pollen will fertilize the female flower and result in a seeded female hop cone. Regardless of pollination, the styles eventually fall off and miniature petals grow which eventually result in a cone-like structure.
Most female flowers develop and ripen predominately between mid-August and mid-September depending on location, weather, and cultural practices. Commercial growers actually delay flowering by removing the earliest vines in the Spring in order to enhance regrowth and encourage a higher yield of flowers. After the flowers ripen, the vine will continue to build reserves until it totally dies back with the first freezes of Fall.
Because hops can produce such a large vine in a matter of months, they will use a large amount of solar energy, water, and nutrients. It is not to say that the hop will not grow under less than optimum conditions, only that the vines will be smaller. Hops prefer full sun and rich soil, preferably light textured, well-drained soil with a pH of 6.5 - 8.0 . If drainage is a problem, small mounds can be built using surrounding top soil mixed with organic matter. Because the hop is a perennial, it's not a bad idea to dig holes about one foot deep so that some manure and other slow release organic fertilizers can be mixed with your soil and replaced into the hole. This puts the nutrients in the root zone.
Rhizomes should be planted vertically with the bud pointing up or horizontally about 1" below the soil surface. First year hops have a minimal root system and require frequent short waterings much like any baby plant, but do not drown it with too much water. Mulching the soil surface with some organic matter works wonders in conserving moisture as well as helps control weeds.
Once the hop is established after the first
season, less frequent deep watering is best, preferably drip irrigation.
Try not to soak the vine during watering, as that will sometimes encourage
diseases. Each Spring apply a hearty dose of manure as a top dressing or
fertilize with a balanced chemical fertilizer that is recommended for garden
vegetables. Don't expect very much in growth or flowers the first year
because the hop is basically establishing it's root system. Full growth
and maximum crops of flowers will be achieved during the second year.
When the young vines are about 1 foot long, 2 to 6 vigorous vines are selected for each hill and the rest removed. 1 to 3 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 sidearms from tangling. Most cones are produced on the upper part of the plant.
In July, the lowest 4 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 the 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.
Space between plants varies from country to country and is mainly based on the need to have enough room to allow tractors to get between the rows. In the United States, hops are grown on 7' by 7' grid with an 18 foot tall trellis. In a home garden, the main concern is just to get the vines off the ground and possible to keep different varieties from getting tangled up with each other. Plant mixed varieties at least 5 ft. apart. Identical varieties can be as close as 3 ft. if you don't have much room. Hops mainly grow up if they can, then lateral siderarms extend off of the main vine. Hops don't have to be grown on an 18' trellis. Some of the less vigorous varieties will yield more if they are limited to 10' - 15'.
Actually just about anything over 6 feet will work, the vine will just become bushier. The vines are easiest to grow and deal with if they are trained onto strong twine. This twine can be supported by a trellis wire, pole, tree branch or building. Small diameter poles, lattice and chain link fence also work but require more hand labor. Keep in mind that the vine does die back each Fall. In the First year vines can be established with a 6 foot stake.
Commercial hop farmers do not train up the first shoots of spring but prune them off mechanically. Hardier shoots are trained onto the string about 4 weeks later (early to mid-May in Oregon). Only 2-3 vines should be trained onto each string with 2 strings per plant. All subsequent vines, which can be extensive with older plants should be cut off. Vines are ready to be trained when they are about 12" long and must be gently wrapped clockwise onto the string without kinking. Once trained, the vine will take care of itself unless you want the vine to grow horizontally, this must be done manually.
Because most hops are produced out of reach from the ground, it is safest to lower the vines in order to pick the hops. The harvest date varies with variety and location but will become evident as you gain experience as a hop grower. At maturity, the hop aroma is at its strongest and is measured by crushing a cone and smelling it. The yellow lupulin glands in the cone become much more evident and plump looking when magnified.
The cone will develop a drier, papery feel and in some varieties
a lighter color as it matures. Some browning of the lower bracts is a good
sign of ripeness. Squeeze the cones as they develop and you will notice
they become more light and resilient rather than green and hard. The actual
picking is self-explanatory and this is where you want the flower cones,
not the leaves. I don't know why raw hop cones are occasionally called
leaf hops, when the idea is to not pick the leaves.
Drying can be done in a good dehydrator, custom made hop dryer, well
vented oven, or they can be air dried. If you use heat, the temperature
should not exceed 140 degrees F. Cooler temperatures take longer but a
higher quality hop is obtained. Under dry weather conditions, I suggest
taking a screen off of your house and setting it up in a wind protected
area, elevated on each end.
Spread the hops as shallow as possible and fluff daily so moist inner cones are brought to the outside of the pile. If weather is dry and the pile is not too thick they will dry in about three days.
A high moisture content in the cones will adversely affect storability
and recipe formulation. The hops are dry when the inner stem of the cone
(strig) is brittle and breaks rather than bends. The strig takes much longer
to dry than the bracts, so be patient. Pack the hops in an air tight container
and store in a freezer until used.
Diseases and Pests
Please note: Most of the pests and diseases have humuli
in the Latin name. This means that they are specific problems on hops and
do not infect or inhabit other plants. Therefore if hops do not have a
history of growing near your location, these problems will hopefully not
exist in your area. Don't let the potential problems of growing hops stop
you anymore than the potential of brewing a bad batch of beer. Mainly because
of the higher heat used in drying commercial hops, the full aromatic potential
may be somewhat diminished. Therefore by using lower drying temperatures
and hopefully organic growing conditions, homegrown hops are the best.
The primary disease in hops is downy mildew. By being specific to hops, the disease may or may not be a problem everywhere. The disease first appears in the spring when some of the shoots develop into 'basal spikes'. The spikes are characterized by a stunted form, pale yellowish-green down curled leaves. The upper surface appears silvery and the underside of the leaf turns black.
Once the shoot develops into a spike it will not continue to grow and should be removed as it is now a source of infection for other parts of the plant as well as other plants. There must be moisture on the leaves in order for the wind-borne spores to germinate. This is why it is a good idea to not sprinkle irrigate. Lower leaves are also often removed as they create a camp area around the basal spikes ideal for spreading the disease.
Downy mildew can be controlled by spraying a copper fungicide such a Kocide 101, but repeated applications may be necessary as rain will wash off the fungicide. Systemic fungicides such a Ridomil and Aliette provide longer protection but may not be available to home gardeners. Hopefully this disease is not a problem in your area, so don't worry about it unless the spikes appear.
Under favorable weather conditions the mildew spreads from these shoots and infects leaves and other shoots. In the summer the leaves of infected vines often turn yellow and the vine may die. Other vines may be dark green and leaves cupped and arms stunted. Cone blight often occurs if favorable moisture conditions are present.
ontrol options for the mildews. The use of Cocide, a copper based fungicide, and sulfer are two possible solutions to controlling both downy and powdery mildews.
The root and crown tissue will have reddish-brown flecks and streaks. This should not be confused with normal reddish tissue found in the center of hop roots and crowns.
Symptoms become particularly common during cool periods following a period that has been favorable for hop growth.
The side arms are shunted and vine growth is poor. Quite often the growing tip of the vines curves downward and becomes brittle and dies. As the new shoots grow this also happens to them. The leaves are dark green and curled downward. The cones may also turn brown and fail to develop.
Yellow ringspots and line patterns develop on the leaves. As the disease progresses the yellow areas die and may evolve the whole leaf.
|Hop Powdery Mildew
Washington Infection Site
Powdery mildew is the oldest of the fungal diseases affecting hops. It caused great damage in the USA when hops were grown on the east coast and was one of the problems that forced the hop industry west where powdery mildew does not occur in commercial hop yards. The disease is characterized by white fuzzy mold growing on both sides of the leaves. If the disease proves to be persistent, it can be controlled with sulfur based fungicides.
Insects can generate large numbers very quickly. Your best defense is to check your plants daily or even twice daily, morning and evening, especially in the early stages of growth. Problems can be corrected and damage reduced if caught early.
|Hop Aphid (Phorodon humuli)
A frequent pest on hops. It passes the winter as an egg on woody hosts of the genus prunus(cherry, peach, plum). Winged aphids move to the top of the plant late in the spring. Aphid populations may build very rapidly and if left uncontrolled may result in defoliation.
This pest is a problem in all hop growing districts of the Northern Hemisphere except some areas in China. If uncontrolled, this insect is capable of completely destroying a crop. The soft green aphids can completely cover the underside of the leaves, sucking the life out of the plant. They can also appear later during cone formation, particularly in cooler weather, and inhabit the inner part of the cone making control next to impossible at this late phase. Black sooty mold grows on the honeydew of the aphid in hop cones and is often the reason for not picking some vines.
The aphid over-winters on various species of Prunus, mainly on sloe (P. spinosa), Damsons (P. institia) and plums (P. demestica). The eggs are laid in the axils of the buds and hatch wingless females in the spring. They reproduce asexually, and soon produce winged females that migrate to the hop. Once on the hop the migrants produce several generations of wingless, asexual aphids that build up in large numbers throughout the summer unless controlled.
The actual aphid has a very soft body and is not hard to kill, but
the tall vines and abundant leaves make it difficult to effectively spray
the vine and hit all the aphids. Organic insecticides such as insecticidal
soap, nicotine and diatomaceous earth work well if effectively applied.
Some success can be derived via the introduction of ladybugs and lacewing
predator insects as long as the predators decide to stay on the hops. The
other option is to spray with a commercial insecticide such as diazinon
|Twospotted Spider Mite (Tetranychus urticae)
Mobile Adult(#1): A serious pest of hops grown in the warm interior valleys of the northwestern United States.
Mite damage (#3)
Spider mites are mainly a problem in hot dry climates. Females over-winter
mainly in the soil or under leaves. In the spring they emerge and climb
up the vines to feed on the lower sides of the leaves. Very small and just
visible to the naked eye, their arrival is more evident by the existence
of their fine white webs on the bottom of leaves. Mites are often not as
big a problem as aphids, so control may not be necessary. Many of the same
insecticides used on aphids are also effective on spider mites. The introduction
of predatory mites is also proving to be a somewhat effective control measure.
Options vary with the intensity of the infestation. Removal by hand, pulling
the leaves off and destroying them, or using a hose to knock them off with
water. Or you can use deterents like pepper sprays or garlic sprays. Planting
borders of flowers such as African marigold, nasturiums and garlic plants
will help deter the numbers in the early stages of growth. Organic insecticides
such as Pyrethrum, insecticidal soap, nicotine and diatomatious earth work
well if effectively applied. Some success can be derived via the introduction
of ladybugs and lacewing predator insects as long as the predators decide
to stay on the hops. But if the infestation has gone unchecked, when discovered,
using commercial insecticides such as diazinon or malathion sprays maybe
your only option to try and save the crop.
An ounce of Prevention is worth a pound of hops.
|Chinook||high||mid to late||alpha/aroma||long with outward bracts|
|Crystal||high||mid to late||aroma||medium, oval|
|Hallertauer||low||early||aroma||loose, small, light|
|Liberty||moderate||mid-season||aroma||small, plump, dense|
|Mt. Hood||moderate||mid-season||aroma||medium, compact|
|Northern Brewer||moderate||mid-season||alpha||medium, loose|
|Perle||moderate||early||alpha/aroma||loose, medium long|
|Saaz||very low||early||aroma||small, light|
|Willamette||moderate||mid-season||aroma||medium, round, light|