The Comprehensive Living Soil Deep Dive

Living soil has become the preferred growing method for cultivators who value plant resilience, flavour expression, and long-term sustainability. Behind the simplicity of "just water" lies a complex ecosystem of microbes, minerals, and organic compounds working in balance. 

1. What Living Soil Really Is
Living soil is more than a growing medium; it's a biological engine. Instead of feeding plants with liquid fertilisers, nutrients are released through microbial action as the plant demands them. Bacteria, fungi, protozoa, arthropods, and earthworms convert organic inputs into plant-available forms, while root exudates direct the microbial community toward what the plant needs at any moment.

A functioning living soil contains organic matter, a stable mineral fraction, aeration components, and a thriving microbial population. Products like Seacliff Organics Living Soil V2 (NZ) or Herbi's Living Soil Growing Mix (NZ) provide ready-made foundations containing balanced amendments and biological diversity. These soils maintain pH stability, retain moisture strategically, and deliver nutrients in a slow, steady way that supports healthier, more expressive plants.

2. Core Components of a Living Soil Mix
A balanced living soil begins with a high-quality base. Moisture-retentive materials, such as peat or coco, are blended with compost or vermicast, along with aeration components like pumice, perlite, or scoria. The goal is to create a structure that remains moist but never waterlogged, with sufficient oxygen for microbial life. Locally produced worm castings, such as Seacliff Organics Worm Castings (NZ) or Mynoke Worm Castings 17L (NZ), play a significant role in the microbial engine that drives nutrient cycling.

The biological component of compost or castings has a significant influence on the soil's performance. Good compost supports disease resistance, nutrient availability, and long-term resilience. For growers building their own soil, a mineralised fertiliser base such as Seacliff Organics Balanced Fertiliser Mix V2 (NZ) or Terra Firma Organic Life (AU) supplies the broader nutrient spectrum required to sustain cycling throughout a full grow.

3. Organic Amendments and Their Roles
Living soil relies on organic, slow-release amendments rather than soluble salts. Each amendment has a unique biological or mineral function, and understanding this helps growers fine-tune soil performance.

A nitrogen foundation may come from balanced organic sources, such as Terra Firma Natural Blood & Bone (AU) or Seacliff Organics Replenish Mix (NZ), both of which release nutrients steadily as microbes break them down. Fish meal, kelp meal, and plant-based meals provide amino acids, micronutrients, and plant-growth compounds that feed both the soil food web and the plant itself over months.

Mineral amendments such as basalt rock dust contribute long-term, slow-release trace minerals. Biochar, such as Seacliff Organics Bio Char (NZ), functions as a stable carbon structure that enhances soil CEC, moderates moisture levels, and provides a habitat for microbial life. Calcium and magnesium are typically supplied via dolomite lime or gypsum, stabilising the structure and supporting enzymatic processes in the root zone.

Biological inoculants deepen the soil's living qualities. Mycorrhizal fungi dramatically extend root systems, increasing access to water and nutrients. Herbi's Mycos Root Booster (NZ) integrates mycorrhizae directly at the root zone to establish early fungal networks. General microbial inoculants, such as Herbi's Living Soil Booster (NZ) and Herbi's Living Soil Starter (NZ), enhance biodiversity and accelerate nutrient cycling in new soil builds or when reusing existing soil.

For AU growers, Nutrifield Substrate Booster (AU) plays a similar role by improving substrate structure, increasing moisture uniformity, and supporting microbial colonisation within soil and soil-like blends.

4. The Science of How Living Soil Works
Nutrient cycling in living soil is a biologically controlled process. Microbes mineralise organic matter into ammonium, which is then converted into nitrate by nitrifying bacteria. Fungi and bacteria release organic acids that solubilise phosphorus and micronutrients otherwise locked in organic material or mineral particles. Chelation binds minerals to organic molecules, keeping them available without causing toxic accumulation.

CEC, or cation exchange capacity, is central to soil performance. The more CEC a soil has, the better it can hold nutrients in the root zone. Components such as humus, compost, clay particles, and biochar contribute to this, reducing leaching and maintaining stable nutrient levels over time.

Living soil naturally regulates pH. Through microbial respiration, decomposition, and buffer mechanisms within humic substances, the pH remains stable even with inconsistent irrigation. Most living soils settle between pH 6.2 and 6.8, eliminating the need for manual adjustment by the grower.

Moisture management is one of the most significant factors influencing microbial function. Living soil thrives in consistent, even moisture conditions rather than rapid wet-dry cycles. Generally, irrigation volumes should be around 5 to 10 per cent of the container's volume. For example, a 22-litre pot receives between 1.1 and 2.2 litres per watering, and a 50-litre pot receives between 2.5 and 5 litres. These smaller, more frequent irrigations keep the soil aerobic, encourage strong root development, and prevent compaction.

Tools such as Blumat sensors or Bluelab Pulse meters help growers dial in moisture accurately and avoid overwatering — the single most common issue in living soil cultivation.

5. Best Practices for Growing in Living Soil
Pot size is foundational. Because living soil is a biologically driven system, larger volumes support more robust microbial activity. A minimum of 20–30 litres works for smaller plants, but most indoor growers achieve optimal results with 40–50 litres or more. Outdoor growers frequently use 100–200 litres or raised beds to allow the ecosystem to establish fully.

Watering should be gentle, consistent, and done with clean, dechlorinated water. Bottled nutrients are rarely required, and overuse can disrupt microbial communities. If supplements are needed, organic materials like kelp, worm castings, compost, or balanced fertiliser blends such as Seacliff Organics Balanced Fertiliser Mix V2 (NZ) or Terra Firma Organic Life (AU) supply nutrients in a biologically friendly form.

Topdressing sustains soil fertility through the cycle. A light layer of compost or castings, paired with a measured amount of mineral and organic amendments, maintains nutrient availability during periods of high demand, such as mid-flower. Seacliff Organics Replenish Mix (NZ) is specifically tailored for this purpose, providing a complete spectrum of nutrients without disrupting the microbial balance.

Mulching helps regulate moisture, prevents compaction, supports fungal growth, and provides habitat for beneficial insects and microbes. Straw, dried leaves, or shredded bark all work well.

6. Pros and Cons of Living Soil
Living soil offers exceptional benefits. Plants grown in biologically rich environments show higher resilience, deeper flavour and aroma expression, and reduced susceptibility to pests and disease. The system self-buffers pH, reduces the need for bottled inputs, and becomes increasingly fertile with each cycle. Environmentally, it is one of the most sustainable growing methods available, with many soils, such as Seacliff Organics Living Soil V2 (NZ), designed to be reused repeatedly with simple top-ups.

However, living soil is slower to correct if issues arise. A deficiency cannot be corrected instantly with a liquid feed; the soil must biologically process the amendments before the plant can access them. Larger pot sizes take up more physical space. Heavy-feeding cultivars may require additional topdressing or microbial reinforcement. And as mentioned earlier, overwatering can stall the entire system.

7. Common Issues and Their Solutions
Overwatering is the number-one challenge. Plants may droop while leaves remain firm, and gnats often appear as an early warning sign. Improving drainage, increasing aeration, or adjusting irrigation frequency typically resolves these problems. Products like Nutrifield Substrate Booster (AU) or biochar amendments (NZ) can help restore structure in compacted soils.

Underfeeding late in the flowering stage is another frequent issue, especially in reused soils. Topdressing with worm castings, compost, and a balanced dry amendment such as Seacliff Organics Replenish Mix (NZ) replenishes nutrients for the final stages of growth. If the soil becomes hydrophobic after drying out, it will repel water. Slow rehydration with repeated small applications, combined with a gentle natural wetting agent like aloe, helps the soil regain proper moisture retention.

8. Advanced Living Soil Techniques
No-till is a popular advanced practice where soil is reused without disturbing the microbial network. Instead of removing roots, stems are cut at the base, and the root mass is left in place to decompose. Each cycle increases biodiversity and soil structure.

Companion planting is another useful strategy. Clover, chamomile, and herbs provide ground cover, nitrogen fixation, and improved microbial activity. Inoculants such as Herbi's Living Soil Booster (NZ) help maintain biodiversity between cycles.

Charging biochar by pre-soaking it in compost, worm castings, or inputs like fish hydrolysate ensures it becomes a microbial habitat rather than drawing nitrogen from the soil. For many growers, biochar becomes a long-term investment in soil structure and fertility.

Living soil isn't just another growing method; it's an ecosystem you cultivate, refine, and learn from over time. When you manage that ecosystem well, it delivers results you can't bottle: richer flavour expression, resilient plant health, and a system that becomes more productive the longer you run it. Whether you're starting with a ready-to-go base like Seacliff Organics Living Soil V2 (NZ) or building your own foundational mix with slow-release amendments such as Terra Firma Natural Blood & Bone (AU), the goal is the same: create a living, cycling, nutrient-rich environment where plants and microbes work together. Get the fundamentals right, trust the biology, and living soil will reward you season after season.