Hops
- Yikes! sorry about all the tiny copy.
lupulus Cultivating hops is easy; all they really need is reasonably fertile
soil, plenty of sunlight and moisture, and something to climb on. Hops
are so vigorous, in fact, that their tendency to run wild in cultivated
fields is commemorated in the second part of their botanical name: Lupulus
means "wolflike." The cone blossoms of the female vine are the best that
homebrewers are concerned about. They contain lupulin, a yellowish powder
that contains the bitter resins and essential oils that give beer its
flavor and aroma. OSU Extension Service Crop Science Report Growing Hops
- In the Home Garden Susan M. Hiller, Gale A. Gingrich and Alfred Haunold1
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. A hop
quarantine in the state of Oregon prohibits hop plants and all plant parts,
except kiln dried cones, from entry into the state directly, indirectly,
diverted or reconsigned. There is an exception for the states of Washington
and Idaho meeting specific conditions. This quarantine was established
to prevent the introduction of diseases. 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. Diseases Downy Mildew 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. Verticillium
Wilt This disease is uncommon in the Pacific Northwest. 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.
Abiotic Wilt 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. Viral Disease
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. Insects 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 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. Prionus beetles, Prionus
spp. Adult beetles may be 1.5 to 3.5 inches long and .75 inches wide.
Their long sweeping antennae may appear sawlike. Larvae are white, fleshy
grubs, without legs. The head is brown with forward-protruding, very strong,
jaws or mandibles. Larvae may be 1.5 to 3 inches in length. They live
in the soil and feed on roots. Harvesting Hop harvest in the Pacific Northwest
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, 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. The harvested
vine can be mulched, burned, 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. 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. 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. |
