Hops (Humulus lupulus)

How well established is this crop?

Initial trial plantings of these crops may have been done. There is little information on plant suitability to the region and no current information on markets, commercial returns or current research. This is a new crop for Otago.

Background

Hops are primarily grown for their use in brewing beer but the plant is also a diuretic, pain reliever, is known to relax spasms, as a sedative and has hormonal and anti-bacterial effects.

Before growing hops a number of considerations need to be taken into account.
People interested in hop farming can contact the Hop Marketing Board to get a set of guidelines spelling out the basic criteria for entry into the industry.

In summary, they are:
Be prepared for a large capital investment, the New Zealand Hop Marketing Board estimate you will need about $2.49 million to set up a 25 hectare hop farm, complete with specialised growing, picking and drying equipment.

Hops are best grown in the Nelson area and all the facilities are there so transport would need to be taken into consideration if considering commercial quantities. However, smaller boutique brewers may be able to utilise the tourist potential in Central Otago.

Growers must meet strict quality assurance standards and be subjected to regular testing.

They must also sign an agreement prohibiting the distribution of N.Z bred cultivars.

Hops may become 6m tall, but die-back to ground level each year. Leaves are long stalked, heart shaped and usually 3-lobed – but can be 5-lobed or 7-lobed and coarsely toothed.

The plants are dioecious (male and female plants are borne on separate plants), the male flowers are in loose bunches 75-125 m long, the female flowers developing into leafy cone-like strobiles about 20 mm across when mature.

Climate

Hops require a warm climate to mature the strobiles.

Winter Chilling and Frosts

Hops tend to be dormant during the worst of the Otago frosts, however out of season events may affect the plant.

Rainfall and Irrigation

Regular irrigation is required, as Hops are heavy users of water, requiring 25-50 mm per week. Some form of monitoring is recommended.

Wind

Hops like full sun, but need shelter from strong winds.

Soil

Hops need good drainage. They are normally grown on deep free draining alluvial soils where waterlogging never occurs.

Sandy loam is preferred, though weed control will be easier on the lighter soils.

Fertility

Hops need a fertile humus-rich soil.

Compost needs to be appied at a rate of 40-70 t/ha or 4-7 kg/m2, in early spring. With large scale operations there is a lot of good compost material from the Hops themselves, as only a very small proportion of the plant is used.

Weed Control

Traditionally hop fields were always cultivated for weed control. However, a shallow-rooted cover crop of White Clover , kept mowed at frequent intervals, will have more benefit, provided there is sufficient irrigation water for the White Clover not to be competing with the hops for moisture.

Varieties

There are many different varieties, including a number recently developed with a much higher content of the bitter principle, alpha-acid. The other major category is aroma hops – it is their essential oils that give beer its characteristic bouquet. Today all the commercial hops grown in New Zealand are bred here too.
‘Super Alpha’ 35% of plantings,
‘Pacific Gem’ 25%,
‘New Zealand Hallertauer’ 20%
with ‘Green Bullet’ and ‘Sticklebract’ making up the remaining 20%.

Pests and Diseases

In general there is only limited pests and diseases that can affect hops. Mites are sometimes a problem, but this is usually a symptom of stress the plants are experiencing. With the increasing understanding of the use of predatory mites such as (Phytoseiulus persimilis) and the realisation that healthy plants resist diseases and pests, it should be possible to manage the problem within organic and bio-dynamic guidelines. Commercial miticides are available.

Layout

Layout and spacing depend on how the hops are being cultivated and how much space is required to accomodate machinery. The plants can be placed 900-1200 mm apart, in rows 1.2-3.0 mtrs apart. Hops may be difficult to eradicate, as they will regrow from seed or small pieces of stem left in the ground.

General Management

The hop vines or stems need to be given something to climb up. They twist upwards in a clockwise direction. Four to twelve vines can be sustained by each plant, depending on spacing. Any extra stems emerging from the crown should be cut back so all the plant’s energy goes into the main ones which are trailed up.

Hops need some means of support that will allow you to harvest the vines. On a large commercial scale, tall poles are set up throughout the hop-garden and heavy wires are permanently strung overhead. Above each plant several twines are attached to these wires and these are pushed about 125mm into the soil, using No 8 wire bent over to form a anchor, or alternatively tie the string to the base of the plant.

Propagation:
Hops are usually propagated from suckers or cuttings. For the cuttings, pieces of stem about 150 mm long with fresh buds on them are taken from under the surface of the soil, where they emerge from the crown.

Hops will also grow from seed, but seedlings would not be true to type and will produce at least 70% of useless male plants. There is some disagreement as to how many male plants are needed: some growers maintain they are not necessary at all, while others keep one or two male plants in about a hectare. The rest being female plants, as only female flowers can be used.

Planting:
Start the cuttings in nursery beds until they have formed roots. Plant the rooted cuttings or suckers in holes in the soil deep enough to cover them vertically.

Timing:
Planting can be carried out in autumn or spring, with autumn being preferred as the plants get off to a better start.

Harvest

The strobiles, or cones are harvested when they are fully developed. They become crisp and the bracts can be pulled out individually without the cone splitting. This is usually late summer to mid-autumn. If left too long, the yellow resin, which contains some of the active principles, will start to fall out.

Equipment

Traditionally hops were picked by hand into large baskets. Today on industrial hop farms, the picking is all done by machine. The vines are cut down and hauled into the machine, which flicks the cones off with wire loops and then puts them through a cleaning process to remove any pieces of leaf.

Hand harvesting is sometimes recommended for 1-2 year old plants, as it can be done without cutting the vines, so it does not set the young plants back much.

Commercial hop operations use suspended drying floors, where the hops are piled 300-600 mm thick and heated air at 70°C or more blown through them. This system leaves a lot to be desired from the point of view of producing hops for medicinal use as virtually all the volatile oils are lost when Hops are dried at this temperature. If being used for medicinal purposes a temperature no greater than 35 degrees C is recommended.

For beer production this does not seem to be a concern, because these will be lost anyway when the beer is boiled, and the brewer is mainly concerned about the bitter components of the hop.

Returns

Hops are not particularly high yielding, estimated at a average of 1000kg/ha per annum.

Contacts

MARKETING
New Zealand Hop Marketing Board
PO Box 3205
Richmond
Nelson
Ph: (03) 544 8989
Email: nzhops@nzhops.co.nz

WHERE TO BUY HOP PLANTS
You can not buy any of the commercial cultivars developed by HortResearch

For small-scale hobbie farmers you can purchase plants from specialist nurseries such as:

Waimea Nurseries
Golden Hills Rd
Richmond
Nelson
Ph: (03) 544 2700

Parva Plants
PO Box 2503
Tauranga
Ph: (07) 552 4902

For further information contact
The Cromwell N