Good Fertilizer for Pine Trees: NPK Guide for Healthy Growth

Pine trees—belonging to the Pinus genus—are iconic evergreens used in landscaping, windbreaks, and native forestry across Australia. Their adaptability and drought-tolerance make them a low-maintenance favourite, but that doesn’t mean fertilisation isn’t important. If your pine tree is showing yellowing needles, stunted growth, or poor branching, it may be time to consider a feeding strategy. In this article, we explore what makes a good fertilizer for pine trees, when and how to apply it, and whether balanced NPK blends like 10-10-10 or 20-20-20 are ideal.

Understanding Pine Tree Nutrition – What Do Pines Need?

Pines are deep-rooted trees that absorb nutrients slowly but steadily. They prefer well-drained, slightly acidic soils and tend to be low feeders once established. However, during the first 5 years or when under environmental stress, they respond well to targeted fertilisation.

Key nutrient needs:

Nitrogen (N): Supports needle growth and green colouration, especially in young trees
Phosphorus (P): Promotes strong root development and shoot elongation
Potassium (K): Boosts disease resistance and overall hardiness, especially in drought
Calcium & Magnesium: Important for cellular structure and chlorophyll production

While native Australian species such as the Hoop Pine (Araucaria cunninghamii) and Slash Pine (Pinus elliottii) are adapted to poor soils, even they benefit from fertiliser in urban or sandy environments. Look for signs like pale green foliage, slower annual growth rings, or poor canopy density to signal nutrient deficiency.

Is 10-10-10 Fertilizer Good for Pine Trees? What’s Better?

The question “is 10-10-10 fertilizer good for pine trees?” often comes up among gardeners and forestry workers. While a 10-10-10 balanced fertiliser can provide general-purpose nutrients, it may not be the most efficient choice for long-term pine tree health. Here’s why:

Young pines thrive with a more nitrogen-forward blend like CompleteGrow 20-20-20 All Purpose Liquid Fertiliser, which encourages needle and branch development
Older trees often need more potassium and phosphorus to support root strength and resilience, making CompleteGrow 4-18-38 + CaMg a better long-term maintenance option
Soil pH and structure affect how well a 10-10-10 blend works—many Australian soils already have moderate phosphorus levels, making high-P fertilisers unnecessary

If you must use 10-10-10, apply it only during early spring and at half strength to avoid shocking the roots. Liquid fertilisers are often better absorbed by conifers, particularly when applied around the drip line and watered in thoroughly. For established trees, fertilise once annually in early spring. For saplings under five years, a twice-yearly feeding schedule—spring and early summer—is ideal. Avoid feeding in autumn as it may promote soft growth vulnerable to frost or pests.

Application Tips, Seasonal Feeding, and FAQ

When feeding pine trees, always apply fertiliser around the root zone (not directly at the trunk). For liquid fertilisers, dilute according to label instructions and water in well. Avoid applying during drought or peak heat unless followed by deep irrigation.

Recommended products:

For young pines: CompleteGrow All Purpose Liquid (20-20-20) – stimulates rapid early growth
For mature pines: CompleteGrow NPK 4-18-38 + CaMg Powder – supports long-term health and drought tolerance

Frequently Asked Questions

What is a good fertilizer for pine trees in sandy soil?
Use a fertiliser high in potassium and calcium, such as the 4-18-38 + CaMg blend, to support cell strength and nutrient retention in sandy soils.

How often should I fertilise pine trees?
Once per year for mature trees in early spring; twice per year (spring and early summer) for saplings or nutrient-deficient trees.

Should I fertilise pine trees in winter?
No. Avoid fertilising during late autumn or winter, as the tree’s metabolic activity slows and nutrients won’t be effectively absorbed.

Can I use lawn fertiliser on pine trees?
Lawn fertilisers are often too high in nitrogen and can burn pine roots or promote unwanted soft growth. Always use a balanced or tree-specific formula.