★★★★★
Definitely works!
We used your 4-18-38 plus cal and mag last season and managed to grow a 78kg pumpkin so it definitely works!
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Limited Time
Reviews
5.0
★★★★★
Based on 9 reviews
Page 1 of 9
Advanced Formula – Boost Flowering & Fruiting – NPK 4-18-38 + Calcium & Magnesium
Price range: $39.80 through $387.00
Designed for maximum flowering and fruit production, with stronger colour, yield and overall vitality.
Complete 3-part nutrient system for flowering and fruiting plants
✅ High-phosphorus NPK 4-18-38 for stronger blooms and heavier fruit set
✅ With calcium and magnesium for firmer, tastier, more colourful fruit
✅ Balanced for hydroponics and soil with steady feeding through every stage
✅ Boosts yield, flavour and bloom density across fruiting plants
Recommended add-on
Save $5.10
1L Fertiliser Sprayer
Made for CompleteGrow nutrients. Make regular feeding easier across pots, garden beds and outdoor plants.
Guided mixing
Copper hose fitting
Bundle price
$45.00
$39.90
Australian Owned & Manufactured
Free Shipping
Limited Time
Boost Plant Growth
NPK 4-18-38 + Calcium and Magnesium
A complete, high-performance nutrient system for vegetables, herbs, and leafy greens. This three-part formula provides all essential macro and micronutrients required throughout every stage of plant growth — from seedling to harvest.
Suitable for both hydroponic and soil-based growing.
This Complete Nutrient Set Includes:
- NPK 4-18-38: High phosphorus and potassium to support & promote flowering and fruiting
- Calcium Nitrate: Promotes strong cell structure and calcium uptake
- Magnesium Sulphate: Supports chlorophyll production and nutrient transport
Guaranteed Analysis:
| Nutrient | Percentage (%) |
|---|---|
| Total Nitrogen (N) | 4% |
| Phosphate (P₂O₅) | 18% |
| Potash (K₂O) | 38% |
Each component is designed to work together for healthy, productive plants.
Feeding instructions and mixing ratios are clearly listed on the package.
Reviews
5.0
★★★★★
Based on 9 reviews
★★★★★
Definitely works!
We used your 4-18-38 plus cal and mag last season and managed to grow a 78kg pumpkin so it definitely works!
★★★★★
Double this seasons harvest
I love my redlove apples and have been finding it difficult to get a good harvest from my plant. After using the advanced formula fertiliser, i just done my first harvest. Fruit is amazing and the tree is holding probably double what it was last season.
★★★★★
High quality fertiliser
I used the Advanced Formula on my tomato plants once they started flowering and the difference has been really clear. The plants pushed more flowers, the fruit set improved and the new growth looks stronger overall. I also like that it includes calcium and magnesium ( very necessary for tomatos), which is exactly what I wanted for keeping the tomatoes growing properly through the season.
Page 1 of 3
Best For These Plants
Perfect for Fruiting Vegetables & Herbs
NPK Fertilizer for Root-to-Bloom Growth
How it Works
Mix all 3 parts
Feed Your Plants
Watch Them Thrive
Flowering & Fruiting Formula
High-Performance Feeding For Bigger Blooms & Better Fruiting
Direct your plant's energy exactly where it counts. This high-potassium ratio shifts plants out of leafy growth and into production, driving flower density, fruit weight and final harvest quality.
Tomato Plants
Heavier trusses, stronger fruit set, better flavour.
Takes over once plants move past early leafy growth and start pushing flowers, trusses and fruit.
- Roma
- Cherry
- Beefsteak
- Truss
See more tomato types
Fruiting Crops
Supports fruit fill, crop load and productive flowering.
Built for crops that need more than leafy growth support once they start putting energy into fruit.
- Capsicum
- Chilli
- Pumpkin
- Cucumber
- Eggplant
See more fruiting crops
Flowering Plants
More flowers, stronger colour, a longer bloom cycle.
For plants where bloom development matters more than soft leafy growth, through the full flowering season.
- Petunias
- Geraniums
- Hibiscus
- Bougainvillea
See more flowering plants
Berries & Vines
Great for fruiting vines and berry-producing plants.
A bloom-and-fruit focused feed for berry crops and climbing fruit through active reproductive growth.
- Strawberries
- Blueberries
- Zucchini
- Melons
See more berries & vines
Roses & Ornamentals
Bigger blooms and richer colour on established shrubs.
Feeds through bud formation and repeat flushes, so plants keep flowering instead of running to leaf.
- Roses
- Camellias
- Gardenias
- Azaleas
See more ornamentals
Hydro & Intensive Grows
Suited to controlled, high-performance growing systems.
For growers running intensive schedules where flowering and fruiting performance is the main focus.
- Greenhouse
- Hydro Crops
- Protected Growing
- High Yield
See more growing systems
Master-Grade Plant Performance
Mix
NPK 4-18-38: 6g / 10L
Calcium Nitrate: 6g / 10L
Magnesium Sulphate: 3g / 10L
Seedling recipe · Dissolve separately · Scoop = 6g
Apply
Water In • Or Use Our Sprayer
Ditch the measuring cups. Our precision sprayer automatically mixes the perfect ratio for you. Just attach to your hose, dial in your feed, and cover your entire garden in minutes with zero guesswork.
| Feeding Level | Mix (1L Bottle) |
|---|---|
| NPK Bag Only | 200g fertiliser + 800ml water |
Want faster, simpler feeding?
Thrive
EXPLOSIVE BLOOMS • SUPERIOR QUALITY
Engineered to maximize floral density, fruit sugars, and structural plant strength.
How Much to Mix
NPK 4-18-38 Mixing Calculator
Choose a recipe (per 10 L), enter litres — we’ll calculate grams for each component.
Dissolve each component separately. Scoop = 6 g.
Reviews From Our Gardener's
Reviews
5.0
★★★★★
Based on 9 reviews
★★★★★
Definitely works!
We used your 4-18-38 plus cal and mag last season and managed to grow a 78kg pumpkin so it definitely works!
★★★★★
Double this seasons harvest
I love my redlove apples and have been finding it difficult to get a good harvest from my plant. After using the advanced formula fertiliser, i just done my first harvest. Fruit is amazing and the tree is holding probably double what it was last season.
★★★★★
High quality fertiliser
I used the Advanced Formula on my tomato plants once they started flowering and the difference has been really clear. The plants pushed more flowers, the fruit set improved and the new growth looks stronger overall. I also like that it includes calcium and magnesium ( very necessary for tomatos), which is exactly what I wanted for keeping the tomatoes growing properly through the season.
Page 1 of 3
Great price very happy with this product. Basil, lettuce, chinese greens, chillies and other herbs. They all look healthy and have their first set of true leaves. Happy with the purchase
Lucas M
Verified Buyer
Delivered so quickly very impressive and I’m using this for hydroponic tomatoes and chilies which look sensational are flowering and fruiting already I’ll buy more💖
Sarah L
Verified Buyer
Fruiting & Flowering Plant Fertiliser – High Phosphorus + Potassium
A premium high-phosphorus fertiliser engineered to drive exceptional flowering and fruiting performance. This fertiliser high in phosphorus and potassium delivers targeted nutrition for abundant blooms, larger fruits, and stronger flavour. Formulated with NPK 4-18-38, Calcium Nitrate, and Magnesium Sulphate, it acts as a complete bloom booster for vegetables, ornamentals, and fruit trees — including citrus, tomatoes, berries, and peppers.
✅ High-phosphorus NPK 4-18-38 for prolific flowering and heavy fruit production.
✅ High-potassium ratio strengthens fruit size, colour, and taste quality.
✅ Includes Calcium & Magnesium for firm fruit, nutrient transport, and plant strength.
✅ Ideal NPK fertiliser for fruit trees & citrus — hydroponic or soil applications.
🇦🇺 Australian-made trusted by growers for consistent, high-yield results.
✅ High-potassium ratio strengthens fruit size, colour, and taste quality.
✅ Includes Calcium & Magnesium for firm fruit, nutrient transport, and plant strength.
✅ Ideal NPK fertiliser for fruit trees & citrus — hydroponic or soil applications.
🇦🇺 Australian-made trusted by growers for consistent, high-yield results.
NPK Ratio
- N 4
- P 18
- K 38
What NPK 4-18-38 Means
Higher P and K to drive budding, flowering and fruit quality while keeping foliage compact.
- Fruiting & flowering: Tomatoes, peppers, berries, cucurbits, roses, citrus.
- Compact growth: Low N helps prevent stretch; pushes blooms & fruit load.
- Already with Cal-Mag: Calcium (19%) strengthens cell walls; Magnesium (9.6%) powers photosynthesis and nutrient movement.
Read More
The 4-18-38 profile prioritises phosphorus and potassium. Phosphorus supports stronger roots and abundant flower initiation, while potassium drives colour, flavour and overall resilience. The modest nitrogen helps prevent stretch, directing energy into blossoms and fruit load. With added Calcium Nitrate and Magnesium Sulphate, plants also receive structural strength, resistance to tip burn, and improved chlorophyll activity.
- Seedling mix and Grow & Bloom recipes included for every stage.
- Gentle on roots; ideal for frequent feeding schedules.
- Works with soil, hydroponics and foliar applications.
FAQ
You get three essential components that deliver complete nutrition for flowering and fruiting plants:
✔️ NPK 4-18-38 — High phosphorus and potassium for strong flowering, fruit set, and colour.
✔️ Calcium Nitrate — Builds firm fruit, prevents blossom end rot, and supports growth.
✔️ Magnesium Sulphate — Boosts chlorophyll, nutrient uptake, and overall plant health.
Fertilisers with a higher K value in the NPK ratio are considered high in potassium. Examples include NPK 4-18-38, 13-13-36, or 0-0-50, which deliver concentrated potassium to enhance fruiting, colour, and flavour.
At CompleteGrow, our NPK 4-18-38 + Calcium & Magnesium is a professional-grade high-potassium fertiliser designed for fruiting and flowering plants. It improves sweetness, firmness, and resilience across a wide range of crops — including tomatoes, peppers, citrus, and berries.
Which fertiliser is high in both phosphorus and potassium?
High-phosphorus and high-potassium fertilisers like NPK 4-18-38 combine the two most important bloom nutrients — phosphorus (P) for root and flower formation, and potassium (K) for fruit size, quality, and colour.
This balanced blend provides full bloom support, making it ideal for plants that need energy for flowering and fruit set, such as tomatoes, strawberries, capsicums, and citrus trees.
What is the best high-potassium fertiliser in Australia?
For Australian growers, CompleteGrow NPK 4-18-38 + Calcium & Magnesium is one of the best high-potassium fertilisers available. It’s crafted for consistent results in hydroponic and soil-based systems, ensuring improved fruit yield, colour development, and disease resistance across all major crops.
High-phosphorus fertilisers have a larger middle number in their NPK ratio — such as NPK 4-18-38, 10-52-10, or 10-30-20.
These blends encourage root growth, early flowering, and strong bud formation, making them ideal for fruiting and flowering plants.
For Australian growers, CompleteGrow NPK 4-18-38 + Calcium & Magnesium is a professional-grade fertiliser high in phosphorus and potassium, delivering powerful bloom and fruit performance.
Fruit trees require a fertiliser rich in phosphorus (P) and potassium (K) to support flowering, fruit set, and sweetness.
A formula such as NPK 4-18-38 provides the ideal nutrient balance for strong root systems and heavy fruit production, while helping prevent leaf drop and poor fruit colour.
When enhanced with Calcium & Magnesium, this blend offers professional-grade performance for citrus, mango, avocado, and stone-fruit trees — suitable for both hydroponic and soil-based growing systems.
