Fig Tree Fertiliser Guide: Best NPK Ratio, Feeding Schedule & Growing Tips

Figs are one of the easiest fruit trees to grow in Australia, but to enjoy a strong harvest, your fig tree needs the right fertiliser at the right time. Whether grown in-ground or in pots, fig trees respond well to balanced, controlled feeding—especially in their active growing season. With the right NPK fertiliser and soil management, you can promote healthy foliage, stronger roots, and sweeter, larger fruit.

In this guide, you’ll learn how to fertilise fig trees for maximum fruit production and long-term plant health, including:

The best fertiliser type and NPK ratio for fig trees
How often to feed fig trees and when to stop
Fertilising young vs mature trees
Common fig tree problems caused by over- or under-feeding

Fig trees (Ficus carica) are low-maintenance once established, but like most fruiting plants, they need proper nutrients to consistently produce high-quality fruit. Too little nutrition leads to pale leaves and small crops. Too much can cause excessive leafy growth at the expense of figs.

Whether you’re growing a Black Genoa, Brown Turkey, White Adriatic, or any other variety, a proper fertilising routine will help your fig tree stay productive and vigorous in Australian conditions.

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Fig Tree Fertiliser: Feeding Strategy

Fig trees are light feeders, but a consistent fertilising routine can significantly improve fruit size, flavour, and overall tree health. The aim is to provide just enough nutrients to support leaf growth without compromising fruit quality, especially during the warm growing months.

Best Fertiliser for Fig Trees

CompleteGrow NPK 4-18-38 + Calcium & Magnesium is the ideal fertiliser for figs, offering a potassium-rich formula that encourages sweet, well-formed fruit and strong, resilient trees. Its added calcium and magnesium improve fruit firmness, reduce splitting, and enhance overall tree health. By focusing on this targeted NPK ratio, your fig tree will get the nutrition it needs without the risk of overfeeding.

Seasonal Feeding Schedule

Spring (Sept–Oct): Begin light feeding every 3–4 weeks to encourage steady canopy and root growth.
Summer (Nov–Feb): Increase feeding to every 2–3 weeks to support fruit swelling, ripening, and improved sweetness.
Autumn (March): Gradually stop feeding to allow the tree to harden off for winter dormancy.

In warmer Australian climates like coastal NSW and QLD, the feeding season may extend further into autumn. Always reduce fertilisation before winter to avoid stimulating soft, frost-prone new growth.

Micronutrients for Sweeter, Healthier Figs

Our formula contains essential trace elements that support healthy fruiting:

Boron – Improves fruit set and prevents internal browning.
Magnesium – Enhances leaf colour and sugar transport to fruit.
Calcium – Boosts firmness, flavour, and resistance to splitting.

By maintaining a consistent feeding routine with CompleteGrow NPK 4-18-38 + Calcium & Magnesium, your fig tree will deliver plump, flavourful fruit and stay vigorous season after season without excessive vegetative growth.

Soil Preparation, Watering & Signs of Nutrient Deficiency in Fig Trees

Fertiliser is only effective if your soil supports healthy root growth and water movement. Fig trees are adaptable, but they thrive in loose, well-drained soil with moderate fertility. Poor soil can cause poor growth, even if you’re fertilising regularly.

Ideal Soil Conditions

Texture: Loamy or sandy-loam soil with added organic matter
pH range: 6.0 to 6.5 (slightly acidic to neutral)
Drainage: Essential—figs hate waterlogged soil and clay

If planting in heavy soil, build mounds or raised beds to improve drainage. For pots, use a premium potting mix with added perlite or bark chips for aeration.

Watering and Fertiliser Absorption

Inconsistent watering can cause fertiliser to leach or become unavailable. Fig trees prefer deep, infrequent watering—especially during hot weather. Overwatering leads to shallow roots and may cause yellowing, even with adequate nutrition.

Signs of Nutrient Deficiency

Pale or yellow leaves: Nitrogen deficiency
Small fruits or fruit drop: Potassium or phosphorus deficiency
Brown spots on leaves: Magnesium deficiency or overwatering stress

Correcting deficiencies involves consistent, moderate feeding. Avoid “rescue doses” of fertiliser, which can burn roots or cause sudden leaf drop. Stick to a gentle, ongoing feeding plan using CompleteGrow NPK 4-18-38 + Cal-Mag and monitor the plant over 1–2 weeks.

Fertilising Potted vs In-Ground Fig Trees

Whether you’re growing your fig tree in a large garden bed or a container, your fertilising routine should be adapted to match the soil volume and root restriction. Potted figs grow faster and fruit earlier, but they also exhaust nutrients quicker and dry out faster.

Fertilising Fig Trees in Pots

Container size: Use a pot at least 45–60 cm wide with good drainage
Feeding frequency: Every 2–3 weeks during active growth
Fertiliser type: Liquid is preferred for even, fast absorption

Because nutrients leach out of pots faster, feed with CompleteGrow NPK 4-18-38 + Cal-Mag to encourage fruit swelling, improved sweetness, and stronger branches.

Fertilising In-Ground Fig Trees

In-ground trees benefit from more stable nutrient conditions but may still require feeding every 4–6 weeks, especially in sandy or nutrient-poor soils. Apply fertiliser around the root zone, avoiding the trunk, and water deeply afterward.

Mulching for Moisture and Nutrition

Mulch around your fig tree with straw, sugarcane, or composted bark to retain moisture and regulate soil temperature. Avoid piling mulch against the trunk. This helps slow nutrient loss and reduces watering needs, especially in summer. Whether in pots or planted in the ground, figs are incredibly rewarding when fed correctly. Using a single, potassium-rich fertiliser like CompleteGrow NPK 4-18-38 + Cal-Mag provides the perfect balance of nutrients for larger, sweeter fruit and long-term tree health.