Citrus australasica
Citrus australasicaUSDA | Grow Zone
9-11Outdoors all year in zones 9 to 11. Anywhere colder, keep it as a houseplant. Protect it below 30°F.
- Light
- Full sun, 6-8 hours
- Water
- Deeply once a week
- Humidity
- 50-70% humidity
- Temperature
- 65-85°F (18-29°C)
- Difficulty
- Intermediate
- Growth
- Moderate
- Mature size
- 6-10 ft tall, 3-5 ft wide
Citrus australasica, known as the finger lime, is a unique citrus fruit native to Australia. Its elongated fruit and tangy flavor make it a favorite among chefs and gardeners alike. Growing this plant not only adds beauty to your garden but also provides delicious, zesty fruit.
Ask Vesper about Citrus australasica
Ideal temperature
65-85°F is where it grows fastest. Below 30°F cold damage starts.
Spacing and harvest
- Mature size
- 6-10 ft tall, 3-5 ft wide
- Plant apart
- 36-60 in
- Frost
- Half hardy: light frost only
Everything it needs
9 essentials at a glance
Watering
Citrus australasica, commonly known as the finger lime, prefers consistent moisture but should not be overwatered.
Water the plant deeply once a week during the growing season, allowing the top inch of soil to dry out between waterings. In winter, reduce watering to every 10-14 days. Signs of overwatering include yellowing leaves and root rot, while underwatering may cause leaf drop and wilting.
Light
This plant thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
Ideal placement includes a south-facing window or outdoor area with ample light. While it can tolerate partial shade, reduced light may lead to slower growth and fewer fruits.
Soil
Citrus australasica prefers well-draining soil with a pH range of 6.0 to 7.0.
A mix of potting soil, sand, and perlite is recommended to ensure good drainage. Avoid heavy soils that retain moisture, as this can lead to root rot.
Humidity
The finger lime prefers moderate to high humidity levels, ideally between 50-70%.
To increase humidity, consider misting the leaves or placing a humidity tray filled with water and pebbles beneath the pot. Signs of humidity stress include brown leaf tips and edges.
Temperature
Ideal temperatures for Citrus australasica range from 65-85°F (18-29°C).
It is hardy in USDA zones 9-11. Protect the plant from temperatures below 30°F (-1°C) and avoid extreme heat above 95°F (35°C), which can stress the plant.
Fertilizing
Use a balanced citrus fertilizer with an NPK ratio of 10-10-10 or similar.
Fertilize every 4-6 weeks during the growing season, and reduce frequency in winter. Signs of nutrient deficiency include yellowing leaves, poor growth, and reduced fruit production.
Pruning
Prune Citrus australasica in late winter or early spring to shape the plant and remove any dead or damaged branches.
Use clean, sharp pruning shears to make cuts just above a leaf node. Regularly remove suckers and any overcrowded branches to improve air circulation.
Repotting
Repot the finger lime every 2-3 years or when it outgrows its container.
Choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes or stunted growth. Carefully remove the plant from its pot, loosen any tightly bound roots, and place it in fresh potting mix.
Propagation
Propagation can be achieved through stem cuttings or seeds.
For stem cuttings, take 4-6 inch cuttings from healthy stems, remove lower leaves, and plant in a well-draining potting mix. Keep the cuttings in a warm, humid environment until roots develop, typically within 4-6 weeks. If using seeds, plant them in a seed-starting mix and keep moist until germination.
When it's unhappy
Yellow leaves
Why it happens
Usually caused by overwatering or nutrient deficiency.
How to fix it
Check soil moisture levels and adjust watering accordingly. Fertilize if nutrient deficiency is suspected.
Root rot
Why it happens
Excessive moisture and poor drainage.
How to fix it
Ensure proper drainage and reduce watering frequency. If root rot is present, remove affected roots and repot in fresh soil.
Leaf drop
Why it happens
Can be caused by underwatering, sudden temperature changes, or pest infestations.
How to fix it
Maintain consistent watering and avoid placing the plant in drafty areas. Inspect for pests and treat accordingly.
Pest infestations (e.g., aphids, spider mites)
Why it happens
Common in indoor environments or during dry conditions.
How to fix it
Regularly inspect the plant and treat with insecticidal soap or neem oil if pests are detected.
Poor fruit production
Why it happens
Insufficient light or nutrient imbalance.
How to fix it
Ensure the plant receives adequate sunlight and fertilize regularly to promote healthy fruit development.
Care through the year
Spring
In spring, resume regular watering and fertilizing as the plant begins to grow actively. Prune any dead or damaged branches to encourage new growth.
Summer
During summer, ensure the finger lime receives full sun and monitor for pests. Water regularly, especially during hot spells, and consider misting to maintain humidity.
Fall
In fall, gradually reduce watering as the plant enters dormancy. Continue to monitor for pests and prepare for cooler temperatures.
Winter
In winter, reduce watering to every 10-14 days and keep the plant in a warm location away from drafts. Fertilizing can be minimized during this period.
Toxicity & Safety
Citrus australasica is generally considered non-toxic to pets and children. However, ingestion of large quantities of any citrus fruit may cause mild gastrointestinal upset. The plant's leaves and fruit should be kept out of reach of pets to prevent any potential issues.
Good to know
How often should I water my finger lime?
Water your finger lime deeply once a week during the growing season, allowing the top inch of soil to dry out between waterings.
What type of soil is best for Citrus australasica?
A well-draining soil mix with a pH of 6.0 to 7.0 is ideal. Consider using a combination of potting soil, sand, and perlite.
Why are my finger lime leaves turning yellow?
Yellow leaves can indicate overwatering or a nutrient deficiency. Check soil moisture and consider fertilizing if necessary.
Can I grow finger lime indoors?
Yes, finger limes can be grown indoors if they receive sufficient light, ideally from a south-facing window or under grow lights.
What pests affect Citrus australasica?
Common pests include aphids and spider mites. Regular inspections and treatments with insecticidal soap can help manage infestations.
How do I propagate finger lime?
You can propagate finger lime through stem cuttings or seeds. For cuttings, take healthy stems, plant them in a well-draining mix, and keep them humid until roots develop.
What is the ideal temperature for finger lime?
Finger lime thrives in temperatures between 65-85°F (18-29°C) and should be protected from temperatures below 30°F (-1°C).
Track this plant in your garden.
Set care reminders, log growth, and join a community of plant lovers.