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?

The best fertiliser for lemon trees is a balanced formula that supports healthy leaf growth, strong roots, and abundant fruit production. CompleteGrow NPK 20-20-20 provides an ideal balance of nitrogen, phosphorus, and potassium for citrus trees, ensuring vigorous growth and consistent yields.

Nitrogen promotes lush green foliage, phosphorus strengthens roots and branch structure, and potassium enhances fruit size, flavour, and overall tree resilience. Regular applications of 20-20-20 help prevent nutrient deficiencies and support year-round tree health.

Apply as a liquid feed using a watering can or hose-end sprayer, soaking the root zone in the early morning or late afternoon to prevent leaf burn.

Common Signs of Deficiency in Lemon Trees

A consistent feeding routine with NPK 20-20-20 will correct and prevent most common citrus deficiencies, such as:

Yellowing leaves: Often linked to nitrogen deficiency.
Leaf drop or premature fruit fall: Can result from inconsistent feeding or low potassium.
Small or poor-quality fruit: Usually caused by a lack of balanced nutrition.

Feeding with a balanced fertiliser like 20-20-20 strengthens the tree and supports better fruit set and flavour.

The Complete Grow Lemon Tree Feeding Program

Spring to early summer: Feed every 3–4 weeks to encourage new foliage and strong branch growth.
Mid to late summer: Continue feeding every 2–3 weeks to support flowering and fruit swelling.
Autumn: Reduce feeding to allow the tree to prepare for cooler months.

CompleteGrow NPK 20-20-20 is the simple, all-in-one solution for lush, productive lemon trees, providing everything they need for strong growth and delicious, homegrown fruit.