Fertilisers 101: Everything You Need to Know

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What Are Fertilisers?

Fertilisers are substances that supply essential nutrients to plants, helping them grow faster, stronger, and healthier. These nutrients—like nitrogen, phosphorus, and potassium—aren’t always present in sufficient amounts in natural soil, especially after repeated planting or in poor-quality soils. Fertilisers help replenish these elements to support ongoing plant health and growth.

The Big Three:

 – Nitrogen: Promotes leafy green growth
– Phosphorus: Supports strong roots, flowers, and fruit

– Potassium: Improves plant health, drought resistance, and disease tolerance

Example: A fertiliser labeled 20-20-20 contains 20% of each nutrient — ideal for balanced, all-round plant feeding.

Types of Fertilisers & When to Use Them

Liquid Fertilisers

Fast-acting and ideal for regular feeding. Perfect for indoor plants, leafy greens, and hydroponic systems.

🌟40% OFF🌟 All Purpose Plant Liquid Fertiliser NPK 20-20-20 & Micro Nutrients

Powdered Fertilisers

Highly concentrated, economical, and ideal for outdoor crops, hydroponics, and general plant feeding.

NPK 20-20-20 Powder Soluble Nutrient Plant Fertsiler & Micro Nutrients

Custom NPK Blends

Need specific ratios for your crop, soil, or setup? We offer made-to-order NPK mixes for commercial use.

Cal-Mag Hydroponic Nutrients Fertiliser

High-Performance Hydroponic Formulas

Specialised nutrients tailored for soilless setups — balanced for rapid growth and productivity.

Commercial Hydroponic Nutrients Hydroponic Plant Grow Part A & B

Why Micronutrients Matter

Micronutrients play a crucial role in plant resilience, productivity, and nutrient uptake.

Cell wall strength, fruit development

Core element in chlorophyll, photosynthesis

Hormone balance, root growth

Supports Respiration & immunity

 

Micronutrient deficiencies often show up as yellowing leaves, stunted growth, or poor flowering — even if NPK levels are good.

Different Plants, Different Needs

Indoor Plants

Slower growth due to low light.
Fertilise every 2–3 weeks at half strength.
Perfect for odour-free formulas like 20-20-20.

💡 Tip: Always water first before feeding to prevent root burn.

 

Vegetables & Edibles

Fast growers with changing needs.
Start with nitrogen-rich fertiliser for leafy growth, then switch to higher phosphorus and potassium during flowering and fruiting.
Weekly feeding supports steady growth and better-tasting harvests.

Ornamental Flowering

Plants like hibiscus and roses need more phosphorus and potassium when blooming.
Feed every 1–2 weeks with a mix like 4–18–38 for stronger stems and brighter blooms.
🌼 Tip: Start feeding at the first sign of buds.

Succulents

Hardy and slow-growing, succulents like aloe and jade benefit from light feeding in warmer months.
Use a diluted, low-nitrogen fertiliser once a month to support colour and structure.
💡 Tip: Let soil dry completely before watering again to avoid root rot after feeding.

How to Calculate How Much Fertiliser You Need

Step 1: Measure Your Space

10m² garden bed? 15 pots? Just get a rough idea of the total area.


Step 2: Use the Label Rate

Apply 4ml per 1L per m² — that’s our standard All Purpose mix, but always check your product label for specific instructions.

Step 3: Multiply Accordingly

Just multiply:
Example — 10m² area × 4ml = 40ml concentrate
Mix into 10L of water and apply evenly.

✅ Tip: Water in well after feeding for best absorption.

Choosing the Right Fertiliser

Plant type

Flowers, vegetables, lawns, or trees — each plant type needs different nutrients and feeding styles.

Growth Stage

Choose based on where your plant is — seedling, growing, flowering, or fruiting — for targeted support.

Soil Condition

Is your soil nutrient-poor or already rich? The right fertiliser will balance and correct deficiencies.

Application Method

Spraying, irrigation, or mixing — each method benefits from the right fertiliser type and formulation.

Need help deciding? Our team can recommend the perfect formula for your setup.

🧲 What Are Chelated Micronutrients?

Chelated micronutrients are trace elements like iron, zinc, and manganese, bound to organic molecules to improve absorption.

This “wrapping” keeps them stable in the soil, especially where pH is inconsistent or extreme. Without chelation, these nutrients often become locked out — meaning plants can’t absorb them even when they’re present.

By using chelated forms, CompleteGrow fertilisers ensure:

  Better nutrient uptake

Less waste and runoff

Stronger, more consistent plant growth

 

 Every bottle of CompleteGrow liquid fertiliser already includes chelated iron, zinc, and manganese — no guesswork required.

 

How It Works

Add to Water

Mix the recommended amount into your watering can

Feed Your Plants

Apply directly to the soil or spray onto leaves

Watch Them Thrive

See healthier, greener, and faster-growing plants in no time

When to Apply: Seasonal Fertiliser Guide

Season What to Use Why It Works
🌱 Spring High-N or Balanced (e.g. 20-20-20) Kickstart leafy growth and early roots
☀️ Summer Bloom/Fruit Boost (e.g. 4-18-38 + CalMag) Supports flowering, fruiting, and resilience
🍂 Autumn Root Boost / Low-N (e.g. 3-12-12) Prepares for dormancy, strengthens roots
❄️ Winter Minimal feeding Avoid overfeeding during dormancy

Customer Q&A / Ask an Expert

Not always. Different plants have different nutrient needs. For example:

  • Leafy greens love high-nitrogen blends like NPK 20-10-10.
  • Flowering and fruiting plants need more phosphorus and potassium, such as NPK 4-18-38.
  • Indoor plants often prefer gentle, balanced formulas like 10-10-10.

Using the wrong fertiliser can slow growth or even damage your plants.

Tomatoes thrive on fruit-boosting fertilisers with extra phosphorus and potassium.
We recommend:

  • NPK 4-18-38 + Cal-Mag – promotes flowering, prevents blossom-end rot.
  • Apply weekly once flowering begins for best yield.

Watch for:

  • Yellowing leaves
  • Slow or stunted growth
  • Poor flowering or fruit
  • Weak stems
    These are all signs your soil might be lacking nutrients.

Yes — micronutrients like calcium, magnesium, iron, and zinc play critical roles in plant health.
Even if your NPK is correct, a deficiency in these can lead to:

  • Leaf curl or burn
  • Blossom-end rot (especially in tomatoes)
  • Chlorosis (yellowing between leaf veins)

Our fertilisers include trace elements or can be paired with Cal-Mag supplements.

Yes — just use a lower concentration and don’t apply to dry soil.
Stick to products like:

  • 🌱 All-Purpose Indoor Plant Food
  • 💧 Liquid NPK with trace elements
    Apply no more than once per week.

Absolutely. We custom-manufacture NPK ratios for:

  • Farms
  • Nurseries
  • Councils
  • Hydroponic setups
  • Distribution

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