What Makes a Good Mulch for Gardens?

Matamata Country Club – Landscape Mulch in a residential setting at Matamata Country Club, Waikato

Mulch is more than just a finishing touch for garden beds — it’s a vital component of healthy, thriving landscapes. From moisture retention to weed suppression, mulch plays a critical role in soil management. But what separates good mulch from the rest?

Let’s explore the essential qualities of high-performing mulch — including one often-overlooked factor: nitrogen stabilisation.

1. Organic vs. Inorganic Mulch

• Organic mulch (e.g., bark mulch, wood chips, straw, compost) breaks down over time, enriching the soil. However, it’s important to choose products that are nitrogen stabilised to avoid nutrient depletion.
• Inorganic mulch (e.g., gravel, rubber, landscape fabric) doesn’t decompose but can be useful for weed control and aesthetics.

For most gardens, organic mulch is preferred for its soil-building benefits, especially when paired with high-quality garden mix and compost.

2. Nitrogen Stabilisation: Why It Matters

When organic mulch begins to decompose, it can temporarily draw nitrogen from the soil — particularly if it’s made from fresh wood chip. This can lead to nitrogen deficiency in plants, causing yellowing leaves and stunted growth.

A nitrogen-stabilised mulch has been aged or composted properly, ensuring it won’t rob the soil of essential nutrients. Stabilised mulch supports healthy microbial activity and maintains a balanced nutrient profile, making it ideal for:

• Vegetable gardens
• Ornamental beds
• Young plantings
• Commercial landscaping projects

Look for products like OrganicGold Eco-Mulch or Landscape Mulch, which are professionally processed to ensure nitrogen stability and optimal soil performance.

3. Moisture Retention

Good mulch helps retain moisture, reducing the need for frequent watering. Composted bark mulch is excellent at holding water while allowing air to circulate — a perfect match for gardens using nutrient-rich garden mix.

4. Weed Suppression

Mulch acts as a natural weed barrier. Materials like OrganicGold’s Eco-Mulch & Landscape Mulch block sunlight from reaching weed seeds, preventing germination and reducing maintenance.

5. Soil Temperature Regulation

Mulch insulates the soil — keeping it cooler in summer and warmer in winter. This protects root systems and promotes consistent growth, especially when combined with compost and garden mix for optimal soil health.

6. Nutrient Contribution

As organic mulch breaks down, it feeds the soil. Nitrogen-stabilised mulch from OrganicGold ensures nutrients are added without depleting existing ones, making it a smart choice for long-term garden health.

7. Appearance and Sustainability

A good mulch should look great and be environmentally responsible. Choose the texture that complements your landscape and opt for sustainable products to reduce your carbon footprint.

Strategic Landscaping – Eco-Mulch & Garden Mix in a commercial setting at the Franklin Day Surgery, Pukekohe, Auckland

Top Nitrogen Stabilised Mulch Picks for NZ Gardens from OrganicGold

• Eco-Mulch – nitrogen-stabilised and ideal for larger areas and riparian projects
• Landscape Mulch – regularly seen in residential and commercial settings
• Growers Compost – nutrient-rich and versatile for all garden types, unlike some composts OrganicGold Growers Compost can be planted directly into
• Garden Mix – a balanced blend of composted bark fines, sheep pellets and OrganicGolds special fertiliser and nutrient blend (containing Biogro & Fertmark registered products)

Final Thoughts

A good mulch supports plant health, improves soil structure, and enhances the look of your garden — but nitrogen stabilisation is key to ensuring it helps rather than harms. Whether you’re a council maintaining public spaces, a contractor landscaping a new development, or a landscape yard supplying bulk material, choosing the right mulch makes all the difference.