A flourishing garden starts with the right nutrients, and slow-release fertilisers are one of the best ways to ensure consistent, long-term plant health. Unlike quick-release fertilisers that deliver nutrients rapidly (often leading to leaching and burn risks), slow-release fertilisers break down gradually, providing a steady supply of essential nutrients over weeks or even months.
In Australia, where weather conditions can vary dramatically, slow-release fertilisers help maintain soil fertility without the need for frequent reapplication. Choosing the right slow-release fertiliser can make all the difference.
In this article, we’ll explore:
Benefits of Using Slow-Release Fertilisers
Why should you consider slow-release fertilisers for your garden? Here are some key advantages:
Long-Lasting Nutrition: Nutrients are released gradually, reducing the need for frequent applications.
Reduced Risk of Burn: Unlike fast-acting fertilisers, slow-release options are gentler on plants.
Environmentally Friendly: Minimises nutrient runoff into waterways.
Cost-Effective: Fewer applications mean less labour and lower long-term costs.
Improved Soil Health: Many slow-release fertilisers enhance microbial activity and soil structure.
For Australian gardeners, these benefits are particularly valuable, as they help plants thrive in diverse climates while conserving water and reducing waste.
How to Choose the Right Slow-Release Fertiliser
Before selecting a fertiliser, consider:
Plant Type: Lawns, flowers, vegetables, and trees have different nutrient needs.
Soil Condition: Sandy soils may require different formulations compared to clay-based soils.
Climate: Hotter regions may speed up nutrient release, while cooler areas slow it down.
NPK Ratio: Nitrogen (N), Phosphorus (P), and Potassium (K) ratios should match your plants’ requirements.
7 Best Slow-Release Fertilisers in Australia
1. ORGANIC LINK Slow Release Fertiliser
Best for: General gardening, lawns, and organic growers
NPK Ratio: Balanced formulation for all-round growth
Key Features:
Made from natural organic materials
Improves soil structure and water retention
Safe for pets and wildlife
Why We Recommend It:
Perfect for those who prefer organic gardening, this fertiliser enriches the soil while providing a steady nutrient supply.
2. ORGANIC XTRA
Best for: Boosting plant vitality and root development
NPK Ratio: Enhanced with micronutrients
Key Features:
Promotes strong root systems
Increases resistance to drought and disease
Ideal for fruit trees and vegetables
Why We Recommend It:
A premium organic option that ensures plants receive not just NPK but also essential trace elements.
3. Turfmaster Fines
Best for: Lawns and turf maintenance
NPK Ratio: High nitrogen for lush green growth
Key Features:
Fine granules for even distribution
Promotes deep root growth
Reduces thatch buildup
Why We Recommend It:
If you want a golf-course-quality lawn, this is the go-to fertiliser.
4. GNP IRON TOPDRESS Fertiliser
Best for: Lawns needing greening & iron-deficient soils
NPK Ratio: Balanced with added iron (Fe)
Key Features:
Combines fertiliser + iron for deep green turf
Corrects yellowing caused by iron deficiency
Granular form allows easy spreading
Works on all grass types including couch, buffalo & kikuyu
Why We Recommend It:
This specialised iron-enhanced fertiliser solves two problems at once: it feeds your lawn while combating that frustrating yellow tinge that plagues many Australian gardens. The slow-release formula means you won’t get that “overnight green-up” followed by rapid burnout that cheaper products deliver.
Pro Tip: Apply in cooler months for best results, and water in lightly to activate.
5. CK 55 Fertiliser
Best for: Professional landscapers & large gardens
NPK Ratio: 17-6-12 + trace elements
Key Features:
Premium controlled-release technology
6-8 month feeding cycle
Contains magnesium, sulfur & iron
Low salt index prevents root burn
Why We Recommend It:
The CK 55 stands out for its extended feeding cycle – a single application can nourish plants for up to 8 months. This makes it ideal for commercial landscapes, council plantings, and homeowners who prefer “set and forget” fertilising.
The inclusion of magnesium promotes chlorophyll production, while sulfur helps with nutrient uptake, particularly beneficial in Australia’s often sulfur-deficient soils.
6. DMR Soil Conditioning Blend
Best for: Rehabilitating poor soils
NPK Ratio: 5-3-2 + organic matter
Key Features:
30% organic compost content
Contains gypsum for clay breakdown
Improves water retention in sandy soils
Encourages microbial activity
Why We Recommend It:
This is a complete soil rejuvenator. The DMR blend is perfect for compacted clay soils, sandy, nutrient-poor gardens, and areas recovering from construction.
The organic matter provides slow-release nutrients while dramatically improving soil structure over time. Many customers report better results in their second year as the soil biology fully activates.
Bonus: Safe to use around native plants and sensitive species.
7. UREA 46-0-0 Nitrogen Fertiliser
Best for: Rapid green growth (with controlled release)
NPK Ratio: 46-0-0 (High nitrogen)
Key Features:
Coated prills for slower release
Most concentrated nitrogen source available
Cost-effective for large areas
Water soluble for flexible application
Why We Recommend It:
While pure urea is typically fast-acting, our coated formulation slows the nitrogen release to prevent burning. It’s particularly effective for sports fields needing quick recovery, pasture and fodder crops, and heavy feeding plants like corn and tomatoes.
Important Note: Best used in combination with other fertilisers to provide balanced nutrition. Always water in thoroughly after application.
How to Apply Slow-Release Fertilisers
For Best Results:
Timing Matters
Lawns: Early spring & autumn
Gardens: At planting time + mid-season
Potted plants: Every 3-4 months
Application Methods
Broadcast spreaders for lawns
Banding for vegetable rows
Top-dressing for established plants
Watering In
Light irrigation activates most products
Avoid heavy watering that could cause runoff
Safety First
Wear gloves when handling
Store in airtight containers
Frequently Asked Questions (FAQs)
Q: How often should I apply slow-release fertiliser?
A: Typically every 2-6 months, depending on the product and plant needs.
Q: Can I use slow-release fertiliser in pots?
A: Yes! It’s excellent for container gardening.
Q: Is slow-release fertiliser safe for pets?
A: Most organic options are safe, but always check the label.
Why Choose Garden Nursery Products?
At Garden Nursery Products, we’re your trusted Gold Coast garden supply specialists. Whether you need fertilisers, pesticides, fungicides, or landscaping supplies, we stock high-quality products to keep your garden thriving. Visit our store or shop online today!
