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Bulletin 4499
By John Burt
June 2001
Contents
Introduction
The tea plant belongs to the Theaceae family and is closely related to the ornamental species of Camellia (japonica, reticulata and sasanqua). The leaves are evergreen, dark glossy green and the white flowers are of small to medium size. The plant is a shrub or a small tree in its natural state, but in commercial gardens it is kept at about one metre high by periodic harvesting. Tea is processed from the immature shoots.
Tea is one of the most important beverages in the World. There are two main types of tea. World production of green tea (Camellia sinensis sinensis) is about 500,000 tonnes and black tea (Camellia sinensis assamica) is about 1,600,000 tonnes.
Green tea is smaller and slower growing and has more distinct serrations on the edges of the leaves than black tea. Green tea has only three to four flushes of active shoot growth per year, whereas black tea is grown in warmer climates and flushes for a longer period. Green tea has more cold tolerance than black tea and requires a dormant period to produce the important first flush in mid to late spring. There is also a difference in processing. Green tea is steamed to prevent fermentation and then dried. It therefore results in a drink that is yellow to green and milk and sugar are not added. Black tea is fermented and dried, thereby producing a brown drink. It is more bitter than green tea, due to higher levels of tannins and flavanols and many people need to add flavourings to make it palatable.
Green tea originated from south-western China and has been used as a beverage and medicine in China since 2700 BC. Britain imported Green tea from China for over 200 years. About 1830 AD, the British discovered native black tea plants in their colony in India, where cheap labour allowed large scale plantations. Its proximity to Europe by sea, also made it cheaper to produce than buying green tea from China. The British therefore changed from drinking green tea to black tea for these reasons. They have since controlled the world marketing of black tea.
Health product
Green tea is mainly used as a beverage as dried tea, but it is also used in the manufacture of biscuits, cakes, canned tea drinks, catechins (supplies anti-oxidants for pharmaceutical products), cosmetic products (skin-care, shampoos), deodorants, filters, ice creams, lollies, soaps, sun-screens, tea bags, toothpaste and towels.
There are numerous scientific papers on the value of green tea as a health product. It contains high levels of anti-oxidants, higher than black tea, that neutralise free radicals in the body. Green tea also differs from black tea, in that it contains a polyphenol and catechin called EGCG (epigallocatechin gallate), which is a powerful anti-oxidant and is thought to be active against cancer. It is also claimed to be useful for reducing levels of cholesterol, blood sugar, diabetes, strokes and blood pressure. Green tea is high in vitamin C and also contains vitamins A, B and E. It contains one third less caffeine than black tea. The caffeine is bound with polyphenols in green tea and is not as available as the caffeine in coffee.
Markets for green tea
World supply and demand for green tea is dominated by China and Japan. They produce 65 per cent and 20 per cent of the world's crop and 85 per cent and 5 per cent of the world's exports respectively. Green tea is also grown in Indonesia, Taiwan and other eastern Asian countries.
With the increasing interest in green tea for health benefits, countries in Western Europe, the USA, Canada and Australia are all increasing their consumption of green tea.
The current consumption of tea in Australia is about 17,000 t of black tea and 2000 t of green tea per year. Production of black tea in Australia is 2000 t per year, mainly from the Atherton Tablelands in Queensland. At present, there is no commercial production of green tea in Australia. The first commercial production of green tea in Australia is likely to be at Bright, Victoria in 2005.
Japanese interest in Australian green tea
Consumption of green tea in Japan is stable at about 100,000 tonnes per year, but domestic production is slowly declining, for several reasons. The area of suitable land for green tea production in Japan is diminishing and the average age of farmers is high, whilst the price of land is very high. Japan imports are 11,000 tonnes of green tea per year and the tonnage is rising, however, the Japanese do not like the quality of green tea from other countries. They have already indicated a preference to import Japanese-style green tea from Australia. Green tea is reported to have poorer flavour if it is stored for long periods, so production of green tea in Australia would provide the Japanese with fresh, out of season, quality tea.
Production of Green tea in Western Australia
The key market for Australian green tea at this stage is the high value market of Japan. Of secondary, but growing importance, are other developed countries including Australia and Germany where consumption of green tea is increasing.
A major Japanese green tea company has shown interest in growing green tea in Australia, primarily for the Japanese market. They consider the Manjimup/Pemberton area (34o South) to be a good area for the production of green tea for their market. This area is similar to the prime Shizuoka area of Japan in latitude, acidic soils and annual average temperature (15o C). Summer temperatures are not too hot and usually do not exceed 35o C. Frosts are not common and mainly occur in winter, when plants will be dormant. The soils are gravelly loams and usually well drained and there are good supplies of quality water for irrigation in the warmer months.
Japanese tea growing areas differ from Manjimup in that they have beneficial higher rainfall, higher relative humidities and less sunshine in summer. However, Japan also has the climatic disadvantages of frosts, cyclones, smog, more pests, farms that are less than one hectare and subsidised production.
A guide to the development of green tea in Western Australia is as follows:
- define the best area to grow green tea (1997)
- introduce varieties from the Eastern States (1999)
- introduce varieties from Japan, establish plants in quarantine and conduct initial propagation (2000 to 2003)
- determine whether plants are likely to grow well in the Manjimup/Pemberton area (2000 to 2002)
- plant Japanese varieties, plant mother plants and conduct trials in the Manjimup/Pemberton area (2001 to 2005)
- if tea growth is promising, commence propagation on a larger scale (2001 to 2007)
- conduct quality tests (2003 to 2007)
- plant 1.0 ha demonstration farm, probably at Manjimup Horticultural Research Institute (about 2004)
- plant 50 hectares of green tea on farms in Manjimup/Pemberton area (about 2008)
- build processing factory in Manjimup/Pemberton area (about 2010).
Introducing plants
The Centre for New Industries Development, Department of Agriculture, believes there is potential for the development of a green tea industry in Western Australia and has investigated the best way of introducing green tea plants. Tea can be imported either as bare rooted plants, or as branches taken from mature plants that can be used for striking cuttings.
Several varieties of green tea have been imported by Department of Agriculture from Japan, and are being established for the mandatory year in quarantine. When pests are found in any imported plant material, the whole batch must be treated with methyl bromide which kills many plants. However, if no pests are found, then fumigation with methyl bromide is not required, but the plants must still be given a routine pesticide dip of white oil, carbaryl and malathion.
Methyl bromide is lethal to the roots of plants, but is not damaging to branches. Shoots have been imported from Japan, treated with methyl bromide and then successfully propagated from cuttings. Where bare-rooted plants have been imported and treated with methyl bromide, cuttings have also been taken from these plants and have grown well.
Department of Agriculture have also obtained plants from Tasmania and Victoria that did not need to be placed in quarantine. These comprised the Okuhikari, Sayamakaori and Yabukita varieties. Adrian and Irene Bowden of New World Flora in Manjimup are also actively involved with the propagation of the above varieties at their Manjimup nursery.
Establishment of small, rooted, plants in a nursery
To establish tea from imported Japanese plants in a nursery, or to pot-on rooted cuttings, the potting mixture should be well drained, well aerated and should not contain salt. Green tea needs an acidic potting mixture, ideally between pH 5.0 to 5.6 (measured in water). A mixture of 72 per cent composted pine-bark, 15 per cent perlite and 13 per cent washed coarse river sand has proved to be suitable at the Australian Quarantine Inspection Service in Victoria.
Plants should be established for the first two months in a greenhouse with 80 to 90 per cent shade. When established, grow preferably in 50 to 70 per cent shade, with a light intensity of 25,000 to 40,000 lux.
Plants appear to establish well in a greenhouse which has evaporative cooling or air conditioning. The plant's environment must be well ventilated. Plants will also establish well outside in full sun in a protected area from April to November. A temperature range of 25 to 30o C is optimum and should not exceed 35<<sup>o C. Night temperatures are optimum at 15o C and should not be lower than 5o C. Frost will severely damage young plants.
One year old bare-rooted plants direct from Japan should be potted up into 13 or 15 cm diameter pots. After establishment, the roots should be frequently examined. If they are too dense on the bottom of the pots, then the plants should be potted up into slightly larger pots. After six to nine months in the nursery, 20 cm diameter pots should be used.
One month after potting-up, apply a seaweed extract to the pots at 1 mL/L to increase the level of beneficial microorganisms in the pots. Then apply a half-strength fish emulsion every one to two weeks to the leaves for one month. The seaweed extract may also be applied every three months.
Two months after potting-up, a slow release fertiliser (six months life) with all the 12 essential nutrients, should be applied at 2 grams per 13 cm pot. This may be repeated at 5 grams per pot, six months later.
After three months, the following fertiliser mixture should be watered onto the pots every seven days (mid October to mid April), fourteen days (mid April to end of May, September to mid October) and monthly (winter).
- sulphate of ammonia at 0.33 grams per litre,
- mono ammonium phosphate (technical grade) at 0.08 grams per litre,
- potassium sulphate at 0.10 grams per litre
- magnesium sulphate at 0.05 grams per litre.
- trace elements boron, copper, iron, manganese, molybdenum and zinc (use the rate on the label)
The potassium sulphate should be dissolved for one hour before use and the other fertilisers may be added to the water just before use. It is important that the nitrogen is applied in the ammonium form and that the level of nitrogen does not exceed 100 ppm. The above mixture applies 78 ppm nitrogen, 19 ppm phosphorus, 42 ppm potassium and 5 ppm magnesium, plus trace elements.
Plants must not be over-watered and should be given hand watering according to the needs of the plants. They must not receive a high level of chlorides or total soluble salts (i.e. less than 75 millisiemens per metre from the irrigation water and no chloride from fertilisers). The pH of the water must not be alkaline. If possible, irrigate with de-mineralised water or rainwater. The plants should also receive a few light sprinklings of water on the leaves each day. The bottom of the pots should frequently be examined to make sure that the plants are not being over-watered. Weed the pots when necessary. Flower buds can be removed if there is sufficient labour.
Propagation
Mother plants, spaced at 2 m by 1 m, need to be grown and maintained as a source of cuttings. One year old nursery plants or tea planted at a commercial spacing can also be used as mother plants.
Shoots should be selected that are showing some browning or hardening on their stems, but are not showing signs of growth from the buds in the nodes. A total of four to six cuttings per shoot should be obtained. Cuttings with one to three nodes/leaves are prepared from the shoots. They should be spaced in a bed at 500 plants/m2. This should be done preferably from October to April in a shaded (90 per cent) greenhouse, but can be conducted at any time of the year.
A well-drained medium such as 25 per cent washed coarse river sand, 25 per cent sieved peat and 50 per cent coarse perlite, or 90 per cent washed coarse river sand and 10 per cent perlite, should be used. The pH should be 5.0 to 5.6 (measured in water). The media should be about 10 cm deep. Cuttings should be inserted at an angle and about 2 cm deep. A good system is to have cuttings with two nodes. It is preferable to retain the leaves on the two nodes, although if there is insufficient space, the leaves may be cut in half. The cutting may be inserted with the first leaf exposed and the second node/leaf may be partly inserted into the potting mixture. If material is short, plant a cutting with one node/leaf. This should be inserted with the node/leaf above the potting mixture and with no nodes/leaves in the potting mixture.
Bottom-heat at 22 to 25o C may be used in winter and IBA rooting hormone at 4000 ppm can also be used, but is not essential. A proprietary mister can be used to mist the plants for a few seconds, every 20 to 30 minutes. This should also be sufficient to supply water to the potting mixture. Temperatures of 25 to 30o C are best for propagation. The area should be well ventilated. Fertilisers are not applied to the cuttings.
After two to three months, when the roots are 2 to 3 cm long, they can be transplanted to 7.5 or 10 cm plastic pots, and later to 13 or 15 cm pots and then to 20 cm pots. One month after the initial potting-up, they should be fertilised weekly with half strength of the green tea fertiliser mixture (see establishment section). The full strength mixture may be applied two months after potting-up. .
Tissue culture is not advised for propagation of tea plants, due to the difficulty and expense of the technology compared with the ease of striking from cuttings. Seeds are also not used for propagation, as seedlings are variable for yield and quality.
Growing green tea in the field
The requirements for a green tea garden are as follows:
- minimum size of five hectares
- well-drained sandy loam or clay loam soil, with depth more than 80 cm
- soil with a pH of 4.5 to 6.0 (measured in water)
- flat, or slope less than 8 per cent
- protected from winds
- more than 10 km from the sea
- no frosts in spring
- few days above 35o C
- irrigated with good quality water in the warmer months.
Management
Trials are being conducted at Manjimup Horticultural Research Institute to determine the best systems for growing green tea. This is especially necessary with regard to soil preparation, fertilisers, irrigation, shading, varieties and weed control.
Field planting can be done with a planting machine 9 to 18 months after propagation. Plants should be hardened in a shade-house and in the open before they are planted. This should not be necessary if they are planted under shade in the field.
With good management, tea may be planted for most of the year, but September to November and March to May are probably the most suitable times.
It is preferable to rip the rows to 40 cm deep before planting to improve drainage. The use of compost at up to 50 cubic metres per hectare will also add organic matter and improve the soil.
A typical spacing for green tea is 1.8 m between the rows and 30 to 40 cm within single or double rows. A total of 13,900 to 18,500 plants are needed for one hectare. Rows running north to south are preferable, but plant on the contour on a sloping site.
Varieties
The requirements of a good variety are as follows:
- easy to strike from cuttings
- strong spreading framework
- limited flowering
- large leaves
- high number of plucking points
- remains suitable for picking for a number of days
- quick recovery after plucking
- good quality
A total of 60 to 80 per cent of green tea in Japan are produced from the Yabukita variety. This has the best taste and quality for the Japanese market. However, other varieties are grown in order to have a range of harvesting periods and to produce blended teas.
Initial planting of the three varieties obtained from the Eastern States show that green tea plants grow well in Manjimup, but quality has not yet been determined. Other varieties obtained directly from Japan and released from quarantine are now being planted.
Pruning
Plants are progressively pruned during establishment, commencing at 15 to 20 cm in the nursery, to obtain a branched framework that will support a large number of plucking points. The plants are then pruned at 20 to 25 cm in the second year, 30 to 35 cm in the third year and 40 to 45 cm in the third year. The final height of the plucking table is 75 to 100 cm. At maturity, there is only a small gap across the rows in the path areas where machinery operates.
In some countries, the time to first plucking is reduced, by using pegs to hold down three to five of the main stems. These are pegged so they slope upwards and can be horizontal to a slope of 45o. Trials with this system will be conducted at Manjimup Horticultural Research Institute.
In Japan, tea is mechanically pruned and harvested in a slightly arched shape, and this may also be a requirement by the Japanese processor in Western Australia. After each season, it will be necessary to prune in autumn or winter to promote vigour and reduce the plucking table to the original level. It may also be necessary to skiff the plucking table, by machine, 10 to 15 days after the first and second harvests in order to remove delayed shoots.
Every five to ten years, to restore vigour, plants will be severely pruned to 30 to 50 cm high.
Irrigation
It is estimated that a total of 7000 to 8000 kilolitres per hectare per year of irrigation water will be needed from sprinklers (12 by 12m apart) in the warmer months in the Manjimup area. Irrigation could also be used to protect the plants from frost, but this may not be necessary. Irrigation would be programmed to activate when the temperature falls to 3o C.
The risers for the sprinklers could be a problem during harvesting, if large mechanical harvesters are used. However, the risers may either be removed or pop-up sprinklers can be used.
Trials are needed to determine whether green tea grows better on trickle irrigation. This would not pose problems with mechanical operations or with shading systems. However, it could not be used for frost control, although the need for this is doubtful. A possible irrigation system is to plant with trickle irrigation (5 year life) and an organic or polythene mulch (1 year life). An organic mulch could be applied annually in years 2 to 4 to reduce weed growth. Sprinklers could be used for watering five years after planting.
The irrigation system can also be used to apply fertilisers.
The irrigation water should be low in salinity. There is no information on this from other tea areas, but it would appear that the water should have an electrical conductivity (salinity) of less than 90 millisiemens per metre. It is possible that slightly saltier water could be used for trickle irrigation.
Mulching
An organic mulch or compost at 20 cubic metres per hectare should be applied over the ground after pruning in winter for the first four years to retain water, reduce weeds and to supply organic matter and nutrients. The choice of mulch depends on the availability of organic material, providing this does not contain salt. Straw or pine mulches have been used successfully in Australia.
Fertilisers
Tea will need to be fertilised monthly from August to March with a balanced fertiliser that contains good levels of nitrogen. It is especially important to fertilise after each plucking. Plants must not be over-fertilised, especially with nitrogen, as this may lead to leaf burning, leaf-fall, excess flowering and a poor taste. However, tea with an optimum level of nitrogen (about 6 per cent) will receive a higher price than tea with a low level of nitrogen (4 per cent). Nitrogen should be applied as sulphate of ammonia and this will also help to acidify the soil.
The suggested total amount of the main nutrients applied per year to mature tea should be:
- nitrogen at 400 kilograms per hectare (sulphate of ammonia at 1900 kilograms per hectare).
- 120 kilograms of phosphorus (685 kilograms per hectare of double superphosphate).
- 240 kilograms of potassium (580 kilograms per hectare of sulphate of potash).
- 100 kilograms of magnesium (1000 kilograms per hectare of magnesium sulphate).
The program should also include two applications per year of a mixed fertiliser such as Nitrophoska Perfect. The latter supplies all the 12 essential nutrients required for plant growth, except molybdenum and includes 15% nitrogen, 2.2% phosphorus and 16.6% potassium. The essential nutrients are nitrogen, phosphorus, potassium, magnesium, calcium, sulphur, boron, copper, iron, manganese, molybdenum and zinc.
Leaf analysis will help to diagnose deficiencies and toxicities in the plants, by comparing the analysis with industry standards. Samples should be taken from the youngest mature leaf of a number of plants. All the essential elements should be checked in the analysis. Special attention must be paid in tea nutrition to nitrogen, phosphorus, potassium, calcium, magnesium and zinc. The level of chloride in the leaves should also be used as a guide to whether the plants are receiving too much salt from the soil and water supplies. Fertilisers should be not applied in the chloride form.
Organic production
We intend to investigate whether green tea can be grown with organic fertilisers and pesticides and marketed as organic tea. This would provide a marketing advantage in Japan and other countries.
Pests
There have been no major problems so far with pests and diseases with black tea in Queensland, or with green tea in the Eastern States.
In Manjimup, careful inspection will be needed for possible problems on the leaves and stems from aphids, apple or garden weevils, caterpillars, rabbits, scales, snails and thrips. On the roots, damage is possible from nematodes, and Armillaria and Phytophthora diseases.
There are few pesticides registered for use on tea in Australia. They include the active ingredients mancozeb (fungicide), fenamiphos (nematocide), summer oil (insecticide) and carbaryl (insecticide).
Weeds
Young tea plants must be kept free of weeds. A good mulch will reduce weeds and has other advantages. A contact registered herbicides that contains the active ingredient glyphosate, may be applied in the cooler months to the paths and around the plants. Green tea has good tolerance to slight spray-drift from glyphosate, but it is best to apply this with a shielded sprayer. Do not apply glyphosate over the plants.
Young tea plants can also be kept free of weeds, except around the planting holes and in the path areas, by planting on black polythene mulch. Trickle irrigation is used with polythene mulch and this would also result in fewer weeds in the path areas.
With established crops, there is little competition from weeds, as there is nearly 100 per cent ground cover from the tea plants. However, weeds must be removed in order that the harvested tea is not contaminated.
Shading
Shading improves the quality of green tea by increasing the level of amino acids and reducing the level of tannins and flavanols. To produce the highest quality green tea, it may be necessary to shade tea in Western Australia. Shade also protects tea from frost and winds. It can also be used to adjust the time for plucking and thereby spread the use of the processing equipment.
In Manjimup, it could be too sunny in summer and processed tea may be too yellow due to exposure in the field to high levels of ultra violet light. This can be corrected by applying shade-cloth (80 per cent density) one week before harvesting, by tractor, so that the shade-cloth rests on the bushes. This would be rolled up by tractor just before harvesting. In Japan, shade as dense as 95 to 98 per cent is used for two weeks before harvesting. Trials will be conducted at Manjimup to determine the need for shading, the shading density and method of shading (permanent overhead shade from planting, or temporary shading before harvesting).
Harvesting
To establish a green tea industry in Western Australia, it will be necessary to plant at least 50 hectares. This is the minimum area needed to support a tea factory, which would cost about $5 million. This would require 0.70 to 1.05 million plants. It is unlikely that one grower will have the resources to plant all the tea required to meet the production needs of one processing factory. Green tea would need to be grown on a number of farms with similar management to supply this factory. The resources of an established tea firm will also be essential to provide capital, processing and marketing experience.
The highest costs with green tea will be in establishment for the first four years. After this time, the plants need to be harvested for a maximum of four times per year in spring and summer, and pruned in autumn or winter. These operations are mechanised. Peak production is at six to eight years. The life of a tea plantation is 30 to 50 years.
The top two leaves and a bud are harvested. Machinery has been developed for harvesting black tea in Queensland that would be suitable for green tea in Western Australia. These harvesters, capable of harvesting up to one hectare per hour, range from about $27,000 for the basic model up to $70,000 for a machine capable of harvesting, pruning, fertilising and spraying the tea plants. The harvesters are lightweight and cause little soil compaction.
Harvesting equipment for a small operation may be a small, portable, two-person harvester. This costs about $3,000 and weighs 10 kilograms. It operates on single rows that are 90 to 120 cm wide. The harvested tea is blown into a large bag that rests on the top of the plucking table and is also held by one of the operators. The total tea picked in a day may range from 700 to 1000 kilograms of wet tea.
Hand harvesting for small boutique operations is slow and one person can only pick 10 to 15 kilograms in one day.
In Manjimup, the first flush will probably be harvested in early November. In Japan, the first flush is worth 1.5 to 3 times more than the combined value of the remaining flushes. It contains more amino acids and less tannins and flavanols. It is therefore sweeter and less bitter than later flushes. The next flush would probably be in late December, and the third flush in mid February. A fourth flush may be harvested in March/April, but this would probably have low value and for quality reasons, may not be harvested.
Processing
Green tea must be delivered to the processing factory within two hours of harvesting and preferably within 20 minutes. Processing involves steaming for 30 to 90 seconds to prevent fermentation, plus cooling, rolling, twisting and drying. The final product is known as 'aracha' and reduces the product weight to about 22 per cent of wet green tea. The aracha would probably be exported to Japan for grading and removal of stalks, dust and impurities. It would be consigned by sea in reefer containers, at 0 to 5o C, in vacuumed bags filled with nitrogen. It would then be packaged and blended with other teas. Dried tea ready for marketing has a moisture level of 5 to 6 per cent.
The aim is to grow green tea for the high-grade market ('sencha') in Japan. This constitutes 20 per cent of the Japanese market. There are many other types of green tea in Japan and in other countries. The main market in Japan is for the lower grade (second, third and fourth flushes) and lower priced 'bancha' tea. The high grade ceremonial tea consists of tea of the first flush that has been grown under shade for the final two weeks before harvest. When processed, it is ground to a powder and is called mattcha. This has been a main part of traditional Japanese culture for hundreds of years. Gyokoro tea is high quality tea that was grown from the first flush under shade, but the tea is not powdered. Jasmine tea consists of green tea plus jasmine flowers. Oolong tea is semi-fermented tea and is produced in parts of China and Taiwan. In China, most green tea is not steamed to prevent fermentation, but is roasted at 90 to 110o C for 40 to 50 minutes. Chinese teas have a milder flavour than Japanese teas.
Quality
Good quality green tea is dark green, with a mild aroma, high amino acids, high nitrogen, and low caffeine, tannins and flavanols. Poor green tea is bitter due high tannins and flavanols. This may be caused by using tea from a late flush, or from plants that have not been plucked at the right time. The plants may also have experienced poor conditions, such as high winds or low temperatures.
Yields
The number of shoots in a 20 by 20 cm quadrat should be 20 to 30. If there are over 30 per quadrat, the tea shoots will be too weak. If less than 20 per quadrat, the shoots may have a high quality, but a low yield.
The aim is to produce 12 to 15 tonnes per hectare of wet tea which is equivalent to 2.6 to 3.3 tonnes per hectare of 'aracha' tea. Yields should be highest for the first flush (3 to 8 tonnes per hectare of wet green tea) and decrease to 2.5 to 3.0, 2 to 2.5 and 2.0 tonnes per hectare for the second, third and fourth flushes respectively. Average yields of wet tea in Japan are only 8.6 tonnes per hectare, corresponding to yields of 'aracha' tea of 1.9 tonnes per hectare.
Economics
It is difficult to predict the economics of growing green tea in Western Australia as the plant has never been grown commercially in the State.
Several assumptions were made in the economic analysis of green tea by a consultant:
- Average price of wet green tea is assumed to be $1.00/kg, with yields of 12,000kg/ha.
- First harvest begins in the fourth year, with full yields in the seventh year.
- Shading is rolled over the crop, one week before harvest and removed immediately prior to harvesting. The expected life of the shade-cloth is eight years.
- 14,000 seedlings are planted per hectare.
- There are five hectares of green tea, planted over three years.
Using these assumptions, over 20 years, a net present value (NPV) of $146,000 was generated over the five hectares. The internal rate of return for the project was 17 per cent. Once the green tea plantation is running, the Year-In-Year-Out gross margin was calculated at approximately $6,400 per hectare.
Changes in the net present value of the project were highly dependent on changes in price paid for green tea. An average price for green tea of 80c/kg reduced the NPV to $6,600 over 20 years, while an average price of $1.50 increased the NPV to $495,000. Removing the requirement for shading increased the NPV to $235,000.
An investment in green tea is net cash flow negative for the first five years, with cumulative payback reached after nine to eleven years.
The largest cost associated with green tea production is labour costs. This cost estimate will therefore need to be refined over the next few years, to determine the cost of production with greater accuracy.
Compared with apples and plums, the returns to green tea appear to be lower, based on current prices from these crops. This must be offset against a much longer expected life for a green tea plantation that may be more profitable in the long term.
Given all the uncertainties surrounding the economic analysis, the crop shows potential at this time. However, in future, there will need to be further investigation into the market potential for green tea, particularly the likelihood of a processing plant being established in Western Australia, before a commercial investment decision can be made.
Further reading
- 'Continued Investigation into the Commercial Production and Development of Green Tea in Tasmania', report by Angela Monks, RIRDC, Canberra, 1999.
- 'Production and Marketing of Green Tea' report by Kate O'Brien, DNRE, Victoria, 2000.
- 'Tea-Culture to Consumption', Chapman and Hall, printers Wilson and Clifford
Acknowledgements
Peter Rowe supplied editing and consulting advice.
Angela Monks of the DPI, Tasmania supplied plants and technical advice.
Disclaimer
1. The advice in this publication is provided to you as a guide only. The State of Western Australia and its employees do not guarantee that this publication is without errors of any kind, or is completely suitable for your particular purposes. New information is being obtained frequently on how best to grow green tea in Western Australia. The State of Western Australia therefore disclaims all liability for any error, loss or other consequence that may arise from you relying on any information in this publication. Due to advances in knowledge and technology, you are advised to obtain your own advice and information from as many credible sources as possible.
2. Users of any agricultural chemical must always read the label and any Permit before using the product, and strictly comply with the directions on the label and the conditions of any Permit. Users are not absolved from compliance with the directions on the label or the conditions of the permit by reason of any statement made or not made in this publication. Please observe the withholding period (minimum days between spraying and harvesting).