Avocados (Persea americana), sometimes called alligator pears due to their distinctive pear shape and rough, textured skin, are a remarkable fruit that stands apart from most others in the plant kingdom. Rather than being high in carbohydrates, avocados are exceptionally rich in healthy monounsaturated fats, particularly oleic acid, making them more akin to an olive than a conventional fruit in nutritional terms.

The flesh is dense, creamy, and buttery, with a mild, nutty flavour that pairs well with a vast array of ingredients. Avocados are highly prized for their nutritional density — they are an excellent source of Vitamin K, Vitamin E, Vitamin C, B-vitamins, potassium, magnesium, and dietary fibre. Their healthy fat content also aids in the absorption of fat-soluble vitamins from other foods consumed alongside them.

Avocados have a long cultural history, with cultivation dating back to at least 500 BC in Mesoamerica, where they were a dietary staple. Today they are grown commercially in warm climates worldwide and have become a globally recognised symbol of healthy eating. The tree itself is handsome and evergreen, making it an attractive addition to larger gardens in suitable climates.

How To Grow

Growing Avocados

Avocados are long-lived, evergreen trees that reward patient gardeners with abundant harvests. They can be grown from seed for interest, but grafted nursery trees are strongly recommended for reliable fruiting.

Starting from Seed

Extract the large stone from a ripe avocado and rinse it clean. Insert three or four toothpicks around its equator and suspend it broad-end down over a glass of water, with the bottom third submerged. Place in a warm, bright spot. Roots and a shoot should emerge within 2–6 weeks. Change the water regularly to prevent bacterial growth. Once the shoot reaches 15 cm, trim it back to 8 cm to encourage bushier growth, then pot on into a rich, free-draining compost mix once it regrows.

> Note: Seed-grown avocados can take 7–13 years to fruit and may not produce fruit identical to the parent variety.

Planting a Grafted Tree

Purchase a grafted avocado from a reputable nursery. Choose a variety suited to your local conditions and space. Plant in a large container or in the ground in a sheltered, sunny position.

Soil

Avocados demand excellent drainage above all else. Root rot caused by waterlogged soil is the primary killer of avocado trees. Use a loamy, well-draining soil with a pH of 6.0–6.5. Raised planting mounds can help in heavier soils.

Sunlight

Full sun is essential — aim for a minimum of 6 hours of direct sunlight per day.

Watering

Water deeply and thoroughly, then allow the top few centimetres of soil to dry before watering again. Overwatering is far more damaging than underwatering for established trees.

Feeding

Feed with a balanced fertiliser formulated for fruit trees or avocados, applying several times during the growing season. Young trees benefit from nitrogen to support vigorous growth; mature trees need a broader nutrient profile to support fruiting.

Pollination

Avocado flowers are classified as Type A or Type B based on the timing of their male and female phases. Planting one of each type nearby improves cross-pollination and significantly increases yields, though some varieties will produce fruit on their own.

Pruning

Light pruning to remove dead or crossing branches and to manage height is beneficial. Avoid heavy pruning, which can reduce fruiting potential.

Container Growing

In climates with cold winters, avocados can be grown in large containers and moved indoors or into a frost-free greenhouse during cold periods. Choose compact or dwarf varieties where possible.

Harvesting

Harvesting Avocados

Avocados are unusual among fruits in that they do not ripen on the tree. They reach physiological maturity while still firm and hanging, and only begin to soften after being picked. Understanding this is key to harvesting at the right time.

Determining Maturity

• Skin colour: Some varieties darken as they mature (e.g. Hass turns from green to purplish-black), while others remain green. Colour alone is not always a reliable guide.
• Size: Familiarise yourself with the expected mature size of your specific variety.
• Test pick: Harvest one fruit and leave it at room temperature for 5–7 days. If it softens evenly to a buttery texture without shrivelling or turning bitter, the rest of the crop is ready.
• Stem test: Remove the small stem nub — if the flesh beneath is green, the fruit is ready; if brown, it may be overripe inside.

Harvesting Technique

• By hand: Gently twist ripe fruit from the stem. Mature avocados detach easily with a light twist.
• Pole picker: For fruit out of reach, use a long-handled harvesting pole with an attached cutter and catching basket to snip the stem cleanly without damaging the tree.

Always cut or twist at the stem, leaving a short stub on the fruit to reduce the entry point for disease.

Post-Harvest Ripening

Store harvested avocados at room temperature (ideally 18–22°C) to ripen over 3–7 days. To accelerate ripening, place them in a paper bag with an apple or banana — the ethylene gas these fruits produce speeds up the process considerably.

Storage

Once fully ripe, avocados can be kept in the refrigerator for up to a week. Cut avocados are best stored with the stone in place and the cut surface covered or rubbed with lemon juice to slow browning.

Staggered Harvesting

If your tree carries a large crop, harvest progressively rather than all at once. Mature avocados can hang on the tree for several weeks once ready without deteriorating significantly, giving you time to manage the harvest sustainably.

Common Problems

Common Problems with Avocados

Root Rot (Phytophthora cinnamomi)

This is the most serious and widespread disease affecting avocado trees worldwide. It is a water mould that thrives in waterlogged or poorly draining soils, causing progressive root death, yellowing leaves, wilting, and eventual tree death. Prevention is critical — always plant in well-draining soil, avoid overwatering, and consider phosphonate fungicide treatments where the disease is known to be present. Once established, it is very difficult to eradicate.

Anthracnose

A fungal disease causing dark, sunken spots on the skin of ripening fruit. It is often spread by wet weather during harvest. Improve airflow through pruning, avoid wetting foliage when irrigating, and apply copper-based fungicide sprays if infection is persistent.

Avocado Lace Bug

Tiny insects that feed on the undersides of leaves, causing stippled, bronzed, or bleached foliage. Severe infestations can weaken the tree. Control with horticultural oil sprays or by encouraging natural predators.

Thrips

Thrips can scar fruit skin and damage young shoots. Silvery or corky scarring on the fruit surface is a telltale sign. Sticky traps and insecticidal soap sprays can help manage populations.

Scale Insects

Various scale insects attack avocado trees, secreting honeydew that encourages sooty mould growth on foliage. Treat with horticultural oils or introduce natural predators such as ladybirds.

Fruit Drop

Premature fruit drop can result from temperature extremes, inadequate pollination, water stress, or nutrient deficiency. Ensure consistent watering during fruit set and apply a balanced fertiliser to support fruit retention.

Sunscald

Direct, intense sun on exposed bark or fruit can cause bleaching and cracking. Whitewash exposed trunks in hot climates and maintain adequate canopy cover.

Wind Damage

Avocado trees have relatively brittle wood and shallow root systems. Plant in a sheltered location and consider staking young trees until they are well established to prevent wind rock.