Family : Myristicaceae
Nutmeg is a perennial evergreen spice tree and a native of Molluccas in East Indonesia. There is some evidence to suggest that the Roman priests may have burned nutmeg as a form of incense. It is also known to have been used as a prized and costly spice in medieval cuisine, used as flavorings, medicines, preserving agents and that was at the time highly valued in the European markets. Nutmeg is reported to have been introduced to Sri Lanka at the beginning of the 19th century but there is evidence that the crop had been brought here even before that by merchants who were traveling on the Silk Road.
Products and Uses
Nutmeg and mace are the main two products. Oils are extracted from both nutmeg and mace. Powdered nutmeg and mace is used in curry powders. Nutmeg and mace are mainly used for culinary purposes to flavor curries and other food products, confectionaries and bakery products. It is also used in the preparation of beverages and drinks. Nutmeg is used as an ingredient in Ayurvedic and Chinese medicine. (Uses of mace and outer rind is not mentioned.)
Major Growing Areas
Nutmeg prefers cooler climates hence mid country areas of Sri Lanka are ideal for the growth of nutmeg. The total extent of Nutmeg in Sri Lanka is 2788ha and from which 80% of the extent is in Kandy district. Other major growing areas are Kegalle and Matale districts.
In Sri Lanka, no specific varieties have been identified. Mother trees are selected considering high yield
(over10,000fruits/tree/yr), regular bearing habit, weight of wet whole nut 30g, size of the nut (wet weight 10g /fruit) and heavy mace (wet weight 1g/fruit). Grafting and air layering both can be successfully done. They can produce fruit bearing female trees.
Soils and Climatic needs
Deep well-drained loams and sandy clay loams rich in organic matter are preferable. Soils with high water table or liable to water logging are unsuitable.
Rainfall – well-distributed rainfall of 1,500-2500mm. is sufficient
Temperature – average annual temperature should be 20-30 C
Altitude – up to 600m
Shade is essential during the first three years of growth. Thereafter exposure to light is beneficial. However cooler, the humid microclimate is much preferred for establishment and fruit setting.
Persistent strong winds are harmful. Sheltered valleys and leeward slopes are best for growing Nutmeg.
Seeds are used for planting. Dark brown full sized seeds of matured fruits from selected mother plants are used for planting. Seeds have to be sown in nursery beds as soon as possible since the viability is lost within 2-3 days. Seedlings are potted in poly bags filled with a mixture of equal parts of topsoil, cow dung and sand. A bout 10g of rock phosphate is also added. Seedlings are emerged from 4 to 8 weeks. Seedlings are kept under shade for about 6-8 months, then hardened and transplanted in the field. If large size plants are needed seedlings of 6-8 months of age are re-potted in bigger poly bags filled with the same mixture and kept for another 9-12 months. Bigger plants establish well in the field. For healthy growth of nursery seedlings, fertilizer solution (1k g urea, 0.75kg TSP, 0.5kg MOP dissolved in 100L of water) can be sprayed. 250ml from above mixture per plant, once a month.
Spacing – 20’x20’ (250 plants/ha.) or 6 x 6m
Planting is done with the onset of monsoon rains. Planting hole is 21/2’x21/2’ in size and is filled with a mixture of topsoil and cattle manure. The collar of the plant has to be at the soil level and the care has to be given not to damage or bending the tap root during the planting. The soil around the plant has to be mulched adequately after the planting.
Temporary shade has to be provided to protect plants from direct sunlight. It is better if temporary shade trees have to be planted before 6-8 months of planting.
Removal of Male Plants
There are separate male and female trees in nutmeg but the sex cannot be identified from outside appearance. The only way for an average farmer to identify the sex of tree is after flowering. Generally, 50% of the seedlings are males. Male trees do not set fruits but are essential for the pollination. Therefore after flowering male trees are removed marinating 1: 10 of male: female ratio. Vacancies are in-filled with new plants.
Recommended mixture – 625 kg/ha at the 10th year and after (density 250 plants/ha)
|Components of the mixture||Parts by weight||Nutrient in the mixture|
|Rock phosphate ( 28 % P2O5)||2||8% P2O5|
|Muriate of potash (K2O)||3||25% K2O|
|Kieserite (24%MgO)||1/3||1% MgO|
The rate of fertilizer application:
|Year||Maha Season (mixture g/plant.)||Yala Season (mixture g/plant.)|
|10 yr. onwards||1250||1250|
Terracing and Weeding
It is essential to bench terrace the base of the seedling particularly in sloping lands initially to a diameter of about 0.5m. and thereafter widen as the plant grows. An inward slope of the terrace will help to reduce the erosion of cut soil.
Weeds must be kept under check. Frequent slashing is recommended and slashed material must be applied to the base of the plant as mulch. For soil conservation and weed control cover crops can be grown. Eg; Stylosanthus.
Diseases and Pests
Nutmeg leaf fall disease
Nutmeg leaf fall disease have been identified an economically important disease reported lately, specially in kandy and Matale Districts. Disease caused by fungi. In initial stages black or brown pin heads can be seen on leaves. In lateral stage all leaves are fallen.
Field sanitation is important to control the disease. In heavier stages fungicides such as Mancozeb NP 80% 10ml dissolved in 10l of water should be sprayed to the canopy when new flush start once a two week. This should be repeated up to 3 months till leaves mature.
Insects feed on leaves, leaf stalk and small stems and suck the cell sap from plants. Heavy infestation dry and die whole plants due to lack of plant nutrients and water. Scale insects secrete the honey dew on feeding site and it act as attractant for ants due to high sugar content. Due to this ants carry the scale insects one place to another and it help to spread the insects. Also sooty mould fungus grow on honey dew secrete surfaces of the plant. Later it will appear as black colour surface. To control the insects cut and burn highly infected plant parts, brush and remove the insects from stems can follow. After that apply the insecticide. Thiamethoxam 25% WG 5g in 10 L of water or Imidacloprid 70% WG 2.5 g in 10 L of water solution spray to the plants.
Harvesting and Post Harvest practices
If well managed, nutmeg starts to bear at the 7th year and harvest increases with time. Productive age of nutmeg is uncertain as it can give good crop more over hundred years. However, peak harvest comes after 20 years of age.
The yield of nutmeg varies from tree to tree from several nuts to 8000-10000 nuts per tree . Average yield is 1500dry nutmeg/tree/year and 1-1.5kgdry mace/tree/year.
As soon as fruits split or about to split they are hand-picked from the trees. Fruits are opened by hand and the mace is removed from the nut by cutting with a small pointed knife where it is attached to the base of the nut. The nuts are dried until the kernel rattles in the shell. Dried nutmeg can be sold as it is or can be shelled and sold only the kernel.
The mace is flattened by hand and dried slowly under the sun until a bright orange-yellow fragrant product is obtained.
Standard quality specifications
Nutmeg seed (with shell)
- Grade 1
- Grade 11
- B.W.P. (Broken, Wormy, Punky)
Nutmeg seed (without shell)
- B.W.P. (Broken, Wormy, Punky)
- Grade I special – Molds and Insects: Shall not be more than 3% by mass in either grade
- Grade 1 – Molds and Insects: Shall not be more than 3% by mass in either grade
- Grade ll – Molds and Insects: Shall not be more than 8% by mass in either grade
Extraneous Matter: Shall not be more than 1% by mass in either grade