wild thyme, common thyme, garden thyme.
a small, upright shrub growing 20-40 cm in height, belongs to the Labiatae
family. Pink to lilac, and rarely white, flowers are borne in clusters
near tips of shoots in early summer. Leaves are small and grey-green.
species of regional importance for both culinary herb and essential oil
production include T. serpyllum, T. zygis and T. mastichina. Lemon-scented
cultivars of thyme are grown on a small scale for fresh and dried culinary
vulgaris is native to the western Mediterranean region, extending to south
eastern Italy. Thymus serpyllum has a wider natural range in much
of western Europe, while T. zygis and T. mastichina are restricted
to the Iberian Peninsula.
and dried thyme is used as a traditional culinary seasoning. The essential
oil is also extracted from the herb and used in both perfumery and flavouring
applications. The essential oil has useful antioxidant activity. Thyme
is also regarded as a medicinal herb with antispasmodic, expectorant and
flatulence-reducing action. Thymol, a major constituent of the oil, has
antibacterial, antifungal and anthelmintic activity.
dried herb is used to give flavour to meat and meat products, condiments,
relishes, soups and gravies. Thyme is an ingredient in mixed herbs. Lemon
thyme is often used to flavour fish dishes.
essential oil of thyme is mainly used in flavouring applications in the
processed food industry. It is also used to fragrance soaps and detergents
where its characteristic fresh, antiseptic aroma is desired.
produces a distinctive honey that is beginning to find niche markets in
Europe and Asia.
is unique among herbs in New Zealand. It became well established over several
thousand hectares of dry, sunny country centred along the Clutha and Kawarau
river valleys in Central Otago. It was probably introduced by gold miners
in the 1860s and 70s. Cockayne reported its naturalisation and spread on
gold tailings near Clyde in 1928, and since then its spread has been rapid.
As rainfall increases towards the coast or the mountains other species
become more dominant and thyme disappears from the flora.
thyme grows without irrigation in very dry conditions, its productivity
is low and increases substantially if irrigation is applied to the crop.
must be very free draining and pH should be increased to at least 6.0 by
applying lime, if necessary.
crop can be established from seed or by cuttings. Some variability in plant
growth habit, flowering time and productivity occurs in a crop established
from seed. Thyme seed is very small but can be sown directly in the field
at a rate of 5 kg/ha. Best results at Redbank Research Station were obtained
by spring sowing in very light, stony soil. Variable crop establishment
is a risk in a direct-seeded crop. Alternatively, seedlings can be established
in a nursery bed or cell trays, and transplanted into the field.
grows easily from 5-10 cm cuttings taken in spring. Root-promoting hormone
may be beneficial. Plants with superior characteristics can be selected
and propagated from cuttings to reduce variability in the crop.
(cuttings or seedlings) can be established in beds approximately 1.5 m
wide. Ideally, beds should be designed so that machinery straddles the
crop and plants are not squashed, which thyme will not tolerate. A spacing
of 25-30 cm between plants in beds is recommended.
tolerates a range of herbicides, although questions of residues on herb
material, particularly for the export market, need to be addressed. No
herbicides are registered for use on thyme, and only limited research has
been carried out. Herbicides showing potential for selective weed control
in Crop & Food Research trials include Sinbar, Stomp, Foresite, Linuron
and Versatill. Although non-chemical weed control may ultimately be desirable,
it may not be possible to grow thyme on a large scale in New Zealand without
some herbicide assistance.
of thyme have been established successfully without herbicides by transplanting
the crop into an area covered with weed-suppressing matting. Organic mulches
can be used in a similar way.
management of a thyme crop is critical. If the crop is left too long between
harvests or is cut too hard, plant death can occur, particularly in wetter
environments. Disease infection may contribute to plant deaths in crops
weakened by heavy cutting. Harvesting should, therefore, be frequent and
cutting height adjusted to leave some green herbage on the plants after
Central Otago, a cultivated crop of thyme was harvested four times in a
season for dried herb production. Harvest was carried out when 10% of the
crop was beginning to flower. Thyme tends to produce new flowers soon after
it has been harvested, so inclusion of some flowers in the final product
suffers from few pests and diseases in Central Otago. However, in wetter
environments with imperfect soil drainage, root-rotting fungal diseases
have been implicated in plant death.
oil yields peak in hot summer conditions. Yields of 1.0% (10 ml oil/kg
fresh thyme) can be expected from wild thyme growing in Central Otago in
mid-summer. Yields decrease to 0.10% in winter. Yields from cultivated
material range from 0.05 to 0.50% depending on variety. However, herbage
yields under cultivation far exceed production in the wild, so more oil
would be produced per hectare in cultivated crops.
tests should be carried out to determine fertiliser requirements. A basal
fertiliser application containing nitrogen, phosphorus, potassium and sulphur
should be applied annually. Thyme responds well to additional applications
of nitrogen during the growing season, usually applied after each harvest
to promote new shoot growth.
large amounts of thyme were sun-dried, but final product quality was poor.
Artificial drying methods allow better control of product quality. A forced
air-flow drier would be suitable. Thyme should be dried at temperatures
lower than 40°C to reduce loss of flavour through volatilisation of
essential oil, and to maintain a good green colour.
dried product must then be processed to remove leaf material from stems,
and sieved to remove dust and produce a uniform product.
International Standard detailing quality requirements for dried thyme is
available. An important factor contributing to the flavour intensity and,
therefore, quality of thyme is the essential oil content of the dried herb.
Whole thyme leaves must contain 0.5% essential oil (5 ml/kg dried herb),
and ground thyme must contain 0.2% essential oil to meet International
oil of thyme can be extracted by steam distillation of the fresh herb.
The essential oil is located in small glands on the leaves. Yield and quality
of essential oil varies according to the genetic make-up of plant material,
crop maturity at harvest, environment and distillation practice.
composition of thyme oil is very variable with seven distinct races (chemotypes)
identified in Europe. Two chemotypes occur naturally in Central Otago,
but the thymol chemotype is dominant. Preliminary assessment by European
flavour and fragrance companies suggested that Central Otago wild thyme
oil is not favoured because it is too unlike their traditional sources
wild thyme resource in Central Otago formed the base of a local dried herb
processing industry in the past. More recently, one or two operators have
harvested thyme mechanically from accessible areas for Cerebos-Greggs.
Yields of around 1000 kg/ha of unprocessed, dried herb could be expected
from wild populations every three years.
of thyme at different locations in New Zealand is given in the table. Good
horticultural management, irrigation, fertiliser and weed control were
used in this study. Recovery of dried leaf after processing depends on
the stalkiness of the material. Cultivated material has a higher proportion
of leaf to stalk than wild material. The percentage of dried rubbed herb
obtained from whole dried herb was around 60-70%.
Indicative yields of thyme
grown at six sites in New Zealand.
of unprocessed dried herb (kg/ha)
failure occurred at Hamilton, Mosgiel and Invercargill through high plant
mortality after a hard crop harvest. Quality of dried herb material produced
in these trials is currently being assessed.
1992: The New Zealand nursery register 1992/93. Reference Publishing Co.
Auckland, New Zealand.
C. (ed. Lord, T) 1991: The plant finder 1991/92 Edition. Headmain Ltd.
R.T. 1989: Andersen Horticultural Library's Source List of Plants and Seeds.
Andersen Horticultural Library, University of Minnesota, USA.
Zealand imports all its dried thyme mainly from Spain and Morocco, the
major world producers. Wild thyme from Central Otago is no longer being
collected commercially because imported material is cheaper. Most bulk
dried herbs are produced in countries with low labour costs, so the challenge
for New Zealand growers is to produce crops of superior quality at a competitive
certain amount of import substitution could be expected, but New Zealand
production would be largely destined for, the export market. Europe is
a major consumer of thyme together with the US. Trade statistics indicate
that the US imports around 1000 t of dried thyme annually. Spot market
prices in the US ranged from NZ$3.70 to 5.40/kg in January 1993 depending
on quality and source: Spanish thyme was offered for higher prices than
percent of the thyme oil of world trade is produced in Spain. The estimated
world production of thyme oil in 1984 was around 25 t. Spain also produced
2 t of wild thyme oil (T. serpyllum) in 1984. The spot price for
thyme oil on the US market was NZ$ 108/kg in January 1993.
& Food Research is continuing research on thyme production in New Zealand.
The crop is being grown at several sites nationwide to assess the effect
of environment on dried herb production and quality. Drying and processing
methods are also being evaluated.
potential of new accessions and chemotypes of thyme for both culinary herb
and essential oil production is being assessed.
7807:Part 2:1989: Herbs and spices for food use. Part 2. Specification
for dried thyme (whole and ground). British Standards Institution, UK.
E. 1949: Oil of thyme. In: The essential oils. Vol. 3. Individual
essential oils of the plant families Rutaceae and Labiatae.
Kreiger, Florida, USAI. pp- 744-763.
H.B. 1981: Source book of flavours. AVI, Connecticut, USA
A.Y. 1980: Encyclopedia of common natural ingredients in food, drugs and
cosmetics. Wiley, New York, USA.
of Agriculture, Fisheries and Food 1980: Culinary and medicinal herbs.
Reference Book 325. Her Majesty's Stationary Office, London, UK.
R.K. 1989: Chemotypic characteristics of Thymus vulgaris L. in Central
Otago, New Zealand. Journal of Biogeography 16: 483-491.
R.K. 1990: Thyme in the Central Otago landscape. In: Kearsley, G.; Fitzharris,
B. ed., Southern landscapes, Department of Geography, University of Otago,
NZ. pp. 213-232.
E.L.; Dann, G.M.; Smith, G.J.S. 1979: Thyme in Central Otago. Tussock Grasslands
and Mountainlands Institute, Lincoln College, NZ. Special Publication
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