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
Discover which CompleteGrow fertiliser suits your plants’ growth stage — from leafy growth to flowering and fruiting.
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.
Or let our calculator do the work for you
CompleteGrow Mixing Calculator
Pick your product and guide, enter the litres you want to make, and we’ll calculate the amount to add.
Choose Your Fertiliser Type
Pick the path that fits your routine: Liquid Concentrate keeps feeding quick and clean, Water-Soluble Powder lets you tune veg vs bloom, and Precision NPK delivers meter-ready accuracy for hydro and drip. Different paths—same destination: strong, steady growth.
Liquid Concentrate
Pre-dissolved nutrient blends (single or A/B) for quick measuring and consistent everyday use.
- Strength:Convenient; no clumping; reliable for small indoor setups.
- Use when:Simple weekly feeds or when scale is small and speed matters.
- Watch:Shake before use; don’t mix concentrates together—add to water separately.
Water-Soluble Powder
Powdered NPK (e.g., 20-20-20 or 4-18-38) that dissolves fully for liquid feed, foliar, or fertigation.
- Strength:Versatile; easy to store and ship; accurate mixing by weight.
- Use when:Routine liquid feeding or stage-specific programs (veg/bloom).
- Watch:Mix order matters: Cal-Mag → base → boosters; check pH last.
Precision NPK
Refined mineral salts blended to exact ratios for predictable, measurable results.
- Strength:Fast uptake; easy to dial EC/ppm to growth stage.
- Use when:Indoor pots, hydro, fertigation, or correcting deficiencies quickly.
- Watch:Measure EC/pH; avoid stacking multiple boosters at full strength.
Store powders dry and sealed; shake liquids before dosing.
🧲 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
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.
When to Apply: Seasonal Fertiliser Guide
Match your feeding to plant cycles. We’ve grouped the best CompleteGrow options for each season, with a quick reason why they work.
- Kickstarts leafy growth & branching
- Builds early root mass for summer
- Supports flowering, fruit set & fill
- Calcium helps prevent blossom-end rot
- Strengthens cell walls for cooler temps
- Improves nutrient uptake & root function
- Hold back on N during dormancy
- Low-dose trace support for houseplants
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
The Grow Blog: News, Tips, & Stories
What is NPK 20-20-20 Fertiliser?
