Origin
Microcitrus australasica, commonly known as the Finger Lime, is a native plant in Australia. It is found in the subtropical rainforest regions in the east coast of the country, particularly in New South Wales and Queensland.
Common Names
Aside from its scientific name and the common name Finger Lime, Microcitrus australasica is also known as Citrus caviar due to its unique fruit appearance and flavor. It is also called Australian Finger Lime, Rainforest Lime, and Green Caviar.
Uses
The fruit of Microcitrus australasica is a popular ingredient in various cuisines. Its caviar-like flesh is rich in citric acid and has a tangy and acidic flavor. The fruit can be used as a garnish for salads, seafood, and meat dishes, as well as in jams, sauces, and marmalades. Moreover, it is also used in the production of cosmetics and essential oils.
The peel of the Finger Lime is also useful. It is used as a natural food coloring, especially in confectionery and beverages. The plant's timber is also used for furniture and cabinetmaking, whereas its bark is used for tanning.
General Appearance
Microcitrus australasica is a thorny shrub or a small tree that grows up to 6 meters tall. Its leaves are small, glossy, and dark green. The plant produces fruits that are cylindrical or oval-shaped, and can be 4 to 8 centimeters long. The colors of the fruit can range from pink, green, yellow, and red, depending on its variety. When cut open, the fruits reveal their pulp that is comprised of small, juicy vesicles similar to caviar. These vesicles vary in color from pale green to pink.
Light Requirements
The microcitrus australasica plant requires full sun to grow. It thrives well in bright light, receiving at least 6 to 8 hours of direct sunlight daily. When planted indoors, the plant should be placed near a sunny window or under a grow light.
Temperature Requirements
The plant grows well in tropical and subtropical climates. It requires a warm temperature range of 60 to 85 degrees Fahrenheit for optimal growth. The plant can tolerate mild winter conditions but requires protection from frost and temperatures below 30 degrees Fahrenheit.
Soil Requirements
The microcitrus australasica plant requires well-draining, fertile soil with a slightly acidic pH range of 5.5 to 6.5. The soil should be rich in organic matter, and the plant benefits from regular applications of nitrogen-rich fertilizers. The plant prefers sandy loam or loamy soil with good drainage and can grow well in pots or in the ground.
Cultivation Methods
Microcitrus australasica, also known as the finger lime, is a small tree or shrub that grows up to 6 meters tall. It can be propagated by seed, grafting, or cutting. The tree prefers well-draining soil, rich in organic matter, and requires a warm climate with temperatures above 10°C. It can tolerate full sun or partial shade, but protection from strong winds is essential.
Watering Needs
For optimal growth, finger lime should be watered regularly, but not excessively. The tree is drought-tolerant but will produce more fruits with regular watering. During the hotter months, the plant requires more frequent watering. Watering should be reduced in the winter, when the tree is dormant.
Fertilization
Finger lime trees require regular fertilization to promote healthy growth and fruit development. A balanced fertilizer with equal parts nitrogen, phosphorus, and potassium should be applied every three months during the growing season. Fertilizer should be sprinkled around the base of the tree, then watered in. Over-fertilization should be avoided, as it may cause damage to the tree.
Pruning
Pruning is essential to maintain the shape of the tree and to promote healthy growth. It is recommended to prune finger lime trees in the spring, after the fruiting season. Dead, damaged, or diseased branches should be removed, as well as any crossing branches that may rub and cause wounds. Pruning should be done with sterilized pruning tools to prevent the spread of disease.
Propagation of Microcitrus australasica
Microcitrus australasica, also known as finger lime, is a citrus plant endemic to Australia. It is widely cultivated for its unique caviar-like pulp, which is used as a garnish or flavoring in various dishes. If you want to grow finger lime in your garden or farm, you have several options for propagation, including seeds, cuttings, and grafting.
Propagation by Seeds
One of the simplest ways to propagate finger lime is by seeds. You can obtain seeds from mature fruits that are fully ripe and have been allowed to dry on the plant. Remove the seeds from the fruit and wash them gently to remove any attached pulp. Soak the seeds in water for a day or two to soften their outer coat and enhance their germination.
Next, plant the seeds in pots or seed trays filled with well-draining soil mix. The soil should be slightly acidic with a pH range of 5.5-6.5. Cover the seeds with a thin layer of soil, then water lightly. Keep the soil moist but not waterlogged, and place the pots in a warm and bright location, such as a greenhouse or a sunny windowsill.
The seeds should germinate within a few weeks to a few months, depending on the freshness and quality of the seeds. Once the seedlings have emerged, you can transplant them to larger pots or to the garden when they reach a height of about 10-15 cm and have developed a few leaves.
Propagation by Cuttings
Another option for propagating finger lime is by cuttings. This method is more reliable and faster than seed propagation, as it ensures that the new plants are genetically identical to the parent plant.
To propagate finger lime by cuttings, select healthy and vigorous branches from the parent plant that are at least 15 cm long and have several nodes. Using a sharp and clean pair of pruning shears, cut the stem at an angle just below a node, removing any leaves or flowers from the lower half of the cutting.
Fill a pot or container with a well-draining soil mix and moisten the soil. Dip the cut end of the cutting into a rooting hormone powder, which will encourage the formation of roots, then place it into the soil, pressing it firmly to ensure good contact. Water the cutting, then cover it with a plastic bag or a transparent container to retain moisture and humidity.
Place the container in a warm and bright location, avoiding direct sunlight or overheating. After a few weeks, check the cutting for root development by gently tugging it. If it resists, it means that roots have formed, and you can remove the plastic covering and gradually expose the plant to more light and air.
Propagation by Grafting
Grafting is a more advanced propagation method that involves joining two plant parts, the scion and the rootstock, to form a new plant. This method is useful when you want to reproduce a specific cultivar of finger lime or to improve the plant's resistance to pests, diseases, or environmental stress.
To graft finger lime, you need to prepare the scion, which is a cutting taken from the desired plant, and the rootstock, which is a seedling or a mature plant of a related citrus species, such as sour orange or lemon. The rootstock should be compatible with the scion and provide a strong and healthy base for the new plant.
The grafting process involves making a clean and precise cut on both the scion and the rootstock, then joining them together by inserting the cut surfaces and binding them tightly with grafting tape or clip. The graft should be done when both the scion and the rootstock are in an active growth phase, usually in spring or summer.
After grafting, you need to keep the plant in a protected and shaded place, such as a greenhouse or a cloche, for a few weeks until the graft union has healed and the plant has started to grow. Once the plant has established, you can transplant it to the garden or a larger pot.
Disease Management
Microcitrus australasica is susceptible to various diseases, such as:
- Phytophthora root rot: This disease is caused by a fungus-like pathogen that attacks the roots, causing wilting and yellowing of the leaves. To manage Phytophthora root rot, avoid overwatering, improve drainage, and treat the soil with fungicides.
- Melanose: Melanose is a fungal disease that affects the fruit and leaves. It causes black spots or lesions on the fruit and cankers on the leaves. To manage melanose, prune infected plant parts, and treat the plant with copper-based fungicides.
- Greasy spot: This fungal disease causes yellow spots on the foliage, which later turn into brown blisters. To manage greasy spot, remove infected leaves, improve air circulation, and apply fungicides.
Pest Management
Microcitrus australasica is also prone to pest attacks by insects that feed on the foliage, fruit, and roots. Some of the common pests that affect the plant are:
- Aphids: These small sap-sucking insects can cause leaf curling, yellowing, and stunted growth. To manage aphids, prune infected plant parts, and use insecticidal soap or neem oil.
- Scale insects: Scale insects feed on the sap of the foliage, causing yellowing and leaf drop. To manage scale insects, prune infected plant parts, and use horticultural oils or insecticidal soap.
- Citrus leafminer: The citrus leafminer lays its eggs on the foliage, and the larvae mine through the leaves, causing silvering and distortion. To manage citrus leafminer, prune infected plant parts, and use insecticides or parasitic wasps.
- Root-knot nematodes: These microorganisms attack the roots, causing galls, stunted growth, and root decay. To manage root-knot nematodes, improve soil drainage, use nematode-resistant plant varieties, and crop rotation.
