Lemon Trees: How to Feed, Grow & Harvest Juicy Lemons

Nothing beats the flavour and aroma of lemons picked straight from your backyard tree. Whether you’re growing in the ground or in a large pot, lemon trees are heavy feeders and need the right fertiliser strategy to produce lush leaves, fragrant flowers, and juicy fruit. This guide covers when to fertilise lemon trees, how to feed them, and the best products to use for consistent results.

Planting & Growing Conditions

Sunlight: Lemon trees need full sun—at least 6 hours of direct light daily. North-facing spots are ideal.
Soil: They prefer slightly acidic, well-drained soil. If planting in clay, mix in compost and sand or plant in raised beds.
Climate: Suitable for most of Australia. In cooler zones (like Melbourne), protect young trees from frost with covers or wrap.

For small spaces or patios, dwarf varieties like ‘Eureka’ or ‘Meyer’ perform well in pots 40–50cm wide. Use a premium potting mix and raise off the ground for drainage.

How to Fertilise a Lemon Tree

Lemon trees are nutrient-hungry. A lack of fertiliser leads to yellowing leaves, small or bitter fruit, and poor flowering. They benefit from two main stages of feeding:

Growth phase (spring–early summer): Focus on nitrogen-rich fertiliser to fuel leaf, stem, and branch growth.
Fruit phase (late summer–autumn): Switch to a bloom-boosting fertiliser rich in potassium and calcium to encourage flowering and juicy, full-sized fruit.

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Seasonal Fertiliser Guide

Knowing when to fertilise your lemon tree is just as important as knowing what to feed. Here’s the general schedule:

Early Spring: Apply a balanced fertiliser to support strong foliage and new shoots as the tree comes out of winter dormancy.
Late Spring to Summer: Continue feeding every 2–3 weeks to sustain growth and encourage flower development.
Autumn: Switch to a bloom and fruit formulation to improve fruit set and prepare the tree for colder months.
Winter: Reduce or pause feeding while the tree rests. Resume once new growth begins.

Feeding Frequency

In-ground trees: Feed every 2–3 weeks during spring, summer, and autumn. Water deeply after feeding.
Lemon trees in pots: Feed more frequently—every 2 weeks—at half strength. Ensure pots have good drainage to avoid root rot.

Mulch around the base (away from the trunk) to retain moisture and protect soil biology. Reapply mulch after each season change or heavy rain.

How Often to Fertilise Lemon Trees in Melbourne

In southern states, fertilise from September to May. Pause feeding during the coldest months (June–August), and restart once the weather warms and new leaves appear.

What Is the Best Fertiliser for Lemon Trees?

Complete Grow offers two premium fertilisers that perfectly suit the growth and fruiting cycle of citrus, including lemon trees.

NPK 20-20-20 – Ideal for early growth stages. Balanced NPK delivers nitrogen for leaf production, phosphorus for root strength, and potassium for resilience. Start applying in spring and continue until flowering begins.
NPK 4-18-38 + Cal-Mag – Designed for the fruiting stage. High potassium promotes fruit size and sweetness, while calcium and magnesium reduce fruit splitting, blossom end rot, and yellowing leaves.

Use a watering can or hose-end sprayer to apply liquid fertiliser directly to the root zone. For best results, fertilise in the early morning or late afternoon to avoid leaf burn.

Common Signs of Deficiency in Lemon Trees

Pale or yellowing leaves: Often a sign of nitrogen or magnesium deficiency. Start with NPK 20-20-20.
Leaf drop or fruit fall: Can be caused by inconsistent watering or lack of calcium.
Small fruit or dry pulp: Indicates low potassium. Switch to NPK 4-18-38 to improve fruit quality.

The Complete Grow Lemon Tree Feeding Program

NPK 20-20-20 – Spring to early summer: for lush foliage, branch strength and tree health.
NPK 4-18-38 + Cal-Mag – Late summer to autumn: for bigger, better fruit with fewer problems.

Explore the full Complete Grow fertiliser range to give your lemon tree exactly what it needs—every season, every stage.