The Cultivation of Finger Lime, although many are unaware, is also possible in Italy. This fruit, known by most as the common name Caviar Lime, is a citrus fruit of Australian origin that has gained attention in recent years. Enthusiasts passionately seek it, especially due to its uses in gourmet cooking. In fact, it is considered a kind of vegan caviar, and therefore its price is sometimes quite high. In reality, even in Italy, the cultivation of finger lime is in the experimental phase. However, it is advanced experimentation, especially in the southern regions where lemons and all other citrus fruits are already cultivated.
In this article, we unveil all the secrets of the caviar lime plant. Additionally, we explore the various available varieties and the specific requirements for healthy and flourishing cultivation.
Origins and Spread of this Exotic Citrus
The finger lime, scientifically known as Citrus australasica or Microcitrus a., is a citrus tree belonging to the botanical family Rutaceae, the same family as kumquats, chinotto, oranges, mandarins, and other citrus fruits. It is native to the rainforests of Australia, specifically the regions of Queensland and northern New South Wales.
However, today this fruit is not only cultivated in Australia but practically all over the world. Even in Italy, the cultivation of finger lime is gaining success, especially in Sicily, the land of citrus excellence. There are also some young companies specializing in caviar lime cultivation along the Calabrian Ionian coast.
The fruits have high commercial value, making it a cultivar to be carefully considered by professional fruit growers to expand their product offerings.
Of course, it is also possible to cultivate the plant in a family orchard, following a few simple precautions.
The Finger Lime Plant
The finger lime tree is a small tree that does not reach large dimensions. In the wild and under ideal conditions, it does not exceed 6 meters in height.
When cultivated, it reaches a maximum height of 2-3 meters.
Occupying little space, therefore, caviar lime is perfect for cultivation in a family orchard.
- The plant has a natural bushy habit, with very short internodes and numerous branches.
- The branches are armed with strong thorns.
- The leaves have a slightly different appearance than typical citrus leaves, with a more rounded shape and smaller size. They are alternately arranged on the branches, numerous, with a crenate margin and pointed apex. They are shiny green on the upper surface, lighter on the lower surface.
- The flowers are numerous and very showy. They are pink-purple in the budding phase and white when they open. Pollination is carried out by beneficial garden insects like bees and other pollinators.
- Flowering at our latitudes occurs in spring, with a tendency to rebloom under the right climatic conditions. This can lead to both maturing fruits and new flowers on the plant simultaneously.
The Fruits of Finger Lime
Fruits are the distinctive feature of the finger lime plant. Among citrus fruits, they have the most variations in terms of color, shape, and size.
- They have a cylindrical appearance (sometimes slightly curved) and can be 4 to 12 cm long.
- They have the typical citrus peel texture, rich in essential oils.
- The external color varies; they can be green, reddish, amaranth, pale yellow, bluish. It depends on the variety being cultivated.
- Inside, they are composed of hundreds of small vesicles, resembling caviar. They are very juicy, and when chewed, they release their flavor, reminiscent of the intense acidity of lemons. Hence the common name “caviar lime.”
- The pulp, like that of all citrus fruits, is made up of small vesicles. The difference in finger lime is that it is free and cascades out. In other citrus fruits, it is contained within the segments’ membranes. The pulp color also varies.
Varieties of Finger Lime
There are various varieties of finger lime. Selection efforts have been particularly active in the last twenty years, carried out by Australian fruit growers starting from wild plants. The most effective propagation method used is grafting, using specially selected parent plants. Seed propagation of this citrus species is not very common due to the long time it takes to reach production and the differences observed with the parent plants.
The most common finger lime varieties are:
- Citrus australasica var. sanguinea Rainforest Pearl. It produces a small-sized tree with an open crown, bearing violet-colored fruits and pink pulp;
- Citrus australasica Alstonville. A larger variety of finger lime, with dark green fruits and light green pulp;
- Citrus australasica Blunobia Pink Crystal. A variety with a medium-sized bushy shrub and compact shape. The fruits have green-brown skin and intense pink pulp.
To start cultivating finger lime, approach specialized nurseries that trade different varieties of exotic fruits. This way, you can obtain certified plants at reasonable prices.
How to Cultivate Finger Lime
Climate Requirements for Finger Lime
Cultivating a finger lime plant is possible in our latitudes. Italy, in fact, is historically known for lemons and oranges. Therefore, there are no particular issues for this more exotic species in the citrus cultivation area. As we know, the limit for citrus cultivation is prolonged frost, thus:
- In northern regions, cultivation is possible only in a greenhouse or in containers, with protection from winter frost.
- Regarding exposure, partial shade is recommended. This is because our summers are becoming hotter due to ongoing climate changes.
- A location sheltered from winds is also preferable.
- A good idea is to plant finger lime trees near taller, shading plants, providing both protection from direct sunlight and winds.
Soil and Fertilization
Cultivating finger lime is successful in soils that have the following conditions:
- The pH value should be between 5 and 6.5, making the soil slightly acidic. Find out how to measure soil pH.
- A loose, deep, and well-draining soil is required.
- Heavy soils, such as clay soils, can lead to waterlogging and root rot.
- Fertilization can be done with a base dressing during planting.
- Continuing fertilization by incorporating ground ground lupines, an excellent fertilizer for citrus.
- For annual fertilization, the best time is the end of winter.
- The soil around the finger lime should be kept covered. Frequent shallow cultivation can harm the delicate root system.
The best time to plant finger lime is the beginning of spring, when there’s no risk of late frost. For planting, follow our general guidelines on planting fruit trees. Planting spacing can be relatively narrow, as the tree doesn’t reach large dimensions. We recommend distances of three meters between plants and four meters between rows.
Training and Pruning
For the training of finger lime, it’s recommended not to make major cuts. Let the plant develop naturally, resulting in a bushy shrub. Forced tree-like shapes with few branches are not advised.
Pruning Finger Lime
As mentioned, in finger lime cultivation, it’s better to follow the plant’s natural form. Pruning should be light and limited. Here are the instructions:
- Heavy cuts can severely damage the plant.
- Pruning can be done after fruit harvesting, starting with the removal of old or damaged branches.
- Interweaving branches can be removed to improve air circulation.
- Sucker growth should be removed.
- Avoid drastic cuts or severe interventions.
Mulching Young Trees
Finger lime plants grow slowly. In the first year after planting, growth might be minimal or nonexistent. To facilitate initial establishment, use a layer of natural straw mulch. This keeps the shallow root system moist and prevents temperature fluctuations. Avoid the mulch touching the plant’s collar, as it can cause wood rot.
Irrigation of finger lime is crucial for balanced growth, particularly during flowering, fruit setting, and maturation in spring and summer. Limited watering is necessary when there’s sufficient natural rainfall. However, during extended drought periods, irrigation is essential. As a result, many growers implement a drip irrigation system.
When Does Finger Lime Bear Fruit?
Finger lime fruits rarely appear before the third year of cultivation. The best production occurs from the sixth year, although there might be alternating fruiting patterns. Spring hailstorms during the flowering period pose a risk to the year’s production, potentially damaging subsequent fruit setting.
Container Cultivation of Finger Lime
Due to its small size, finger lime can be grown in pots, extending cultivation possibilities beyond geographical limits.
Pot-protected plants are more manageable compared to those in open fields, especially against frost. Avoid moving plants indoors; instead, protect them using non-woven fabric covers. As an option, position plants under a porch or balcony greenhouse for added protection. Since finger lime plants are typically purchased in pots, they need periodic repotting. Do this in the first spring. Subsequently, repot every two years, up to a container with an 80 cm diameter, which will be the final container size. Use specific citrus soil for every repotting. Include expanded clay pellets at the bottom of the pot for drainage and avoid overfilling the saucer with water. Given the tendency for potting soil to dry faster, pay close attention to watering. Check the soil’s moisture level before watering.
Diseases and Pests
Like other citrus species, finger lime can be susceptible to fungal diseases. For further information and appropriate interventions, read our in-depth articles. Regarding citrus pests:
Regarding citrus diseases:
- Citrus canker;
- Blue mold.
Cultivating Finger Lime: Summary
In summary, successful finger lime cultivation involves these steps:
- Ensure your location is suitable for citrus cultivation,
- Choose a wind-protected and frost-free site,
- Prepare slightly acidic, loose, deep, well-draining, and fertilized soil,
- Use a planting spacing of 3 meters by 4 meters,
- Avoid unnecessary pruning,
- Mulch young trees,
- Irrigate as needed,
- Apply appropriate biological remedies for pests and common citrus diseases.
Nutritional Properties and Uses of Finger Lime Fruits
Finger lime is highly sought after in gourmet restaurants. The small, juice-filled vesicles are used in elaborate, expensive dishes. They release an intense flavor upon chewing. This explains the high market value of fresh fruits.
In the early years of its introduction to the market, there were price fluctuations. Prices sometimes reached €180.00 per kilogram, a high cost for a fruit that can be cultivated by anyone. Market regulation is expected, resulting in accessible prices and a thriving trade. For those growing finger lime domestically, it’s important to know the fruit’s nutritional benefits. It’s rich in vitamin C, vitamin B6, folic acid, and minerals. It possesses antiseptic and refreshing properties, aiding digestion. Finger lime can be transformed into syrups and jams, allowing the enjoyment of this unique and precious fruit at any time.