NPK 20-20-20: The Complete Guide for Australian Gardeners
If you want one fertiliser that covers all the bases, NPK 20-20-20 is where most Australian gardeners start. It’s a fully balanced blend — equal parts nitrogen, phosphorus and potassium — built to support healthy foliage, strong roots and better yields in a single application, whether you’re tending a few pots on the patio or managing a working farm.
This guide walks through what’s actually in the bag, how to mix and apply it correctly for your setup, and how it compares to our other specialised blends — so you can feed your plants with confidence rather than guesswork.
Why Choose NPK 20-20-20 Fertiliser?
NPK 20-20-20 is a premium, evenly balanced fertiliser — the “20-20-20” in the name is the exact percentage of each core nutrient, so there’s no guessing which one is dominant.
| Nutrient | Content | What It Does |
|---|---|---|
| Nitrogen (N) | 20% | Drives lush, green growth and healthy foliage |
| Phosphorus (P) | 20% | Encourages strong roots and vibrant flowers |
| Potassium (K) | 20% | Boosts overall plant health, resilience and fruit development |
| Trace Elements | Magnesium, Zinc, Iron, Boron | Rounds out the nutrient profile for complete, all-round plant health |
Built for Australian Conditions
Whether you’re growing vegetables, fruit, flowers or ornamentals, NPK 20-20-20 is formulated to perform across Australia’s diverse climates — from humid coastal gardens to dry inland properties. It scales just as well too, meeting the needs of a small backyard patch and a large commercial operation alike.
Application Guide for Home Gardens
NPK 20-20-20 is fully water-soluble and easy to mix. The rates below are general starting guidelines for home gardens. For accuracy, weigh the powder rather than relying on teaspoons, as the weight of a teaspoon varies with the product’s granule size and density.
Note: More is not better. Mixing stronger than these rates won’t speed up growth — it can burn roots and leaves. If plants show brown leaf tips or a white crust on the soil, ease off and flush pots with plain water.
| Use | Preparation | Application | Frequency |
|---|---|---|---|
| Indoor & outdoor potted plants | Dissolve 1–1.5 g per litre of water (10–15 g in a 10 L watering can). Use the lower rate for indoor plants and sensitive plants. Tap water or rainwater is fine. | Water the potting mix until it is evenly moist and a little drains from the base. If the mix is bone dry, water with plain water first. | Every 2–3 weeks during active growth in spring and summer; reduce to every 4–6 weeks or pause during slower autumn and winter growth |
| Small vegetable beds & flower gardens | Dissolve 15–20 g in a 10 L watering can (1.5–2 g per litre). Tap water or rainwater is fine. Start at the lower rate and assess plant response before using the higher rate. | Spread each 10 L can over about 3–5 m², aiming at the soil around plants rather than the leaves. Water dry beds first. | Every 2–3 weeks during active growth; adjust to crop requirements, soil conditions and the product label |
A few quick tips: stir until the powder is fully dissolved before applying, feed in the cool of the morning or evening rather than in hot sun, and mix only what you’ll use that day. Store the bag sealed, in a dry place out of reach of children and pets. For a more detailed fertigation plan, use our smart planner tool.
Australian natives: Many natives — especially banksias, grevilleas, hakeas and waratahs — are sensitive to phosphorus. Don’t use NPK 20-20-20 on them; choose a low-phosphorus native fertiliser instead.
Application Guide for Large Gardens, Farms & Orchards
Managing a larger property calls for rates that scale efficiently. Here’s how to apply NPK 20-20-20 across field crops, greenhouse crops and orchards. Foliar rates are given as a spray concentration (to protect leaves) and, where relevant, a per-hectare rate.
| Use | Method | Rate | Timing / Frequency |
|---|---|---|---|
| Field crops (wheat, barley, canola, etc.) | Foliar spray | 1–2 kg per hectare; keep the spray solution at or below 1% (10 g per litre) | 1–2 applications during early vegetative growth — cereals from tillering to early stem elongation, canola from rosette to early bolting |
| Field crops (wheat, barley, canola, etc.) | Irrigation (fertigation) | 25–50 kg per hectare per application (250–500 g per 100 m²) | 2–4 applications during active vegetative growth; set the season total from a soil test |
| Greenhouse crops (tomatoes, cucumbers, eggplants, etc.) | Foliar spray | 1–2 g per litre (200–400 g per 200 L water) | Every 1–2 weeks as a supplement to root feeding; spray early morning, never in hot midday sun |
| Greenhouse crops (tomatoes, cucumbers, eggplants, etc.) | Irrigation (drip) | 0.5–1 g per litre of irrigation water (about 100–200 ppm nitrogen), injected at every irrigation | Constant feed from transplant; from flowering and fruit set, switch to or alternate with NPK 12-12-36 |
| Orchards & large trees | Foliar spray | 2.5–3 kg per 1,000 L water (0.25–0.3%) | 2–3 sprays, 2–3 weeks apart, from petal fall through fruit development; avoid spraying open blossom |
| Orchards & large trees | Irrigation (fertigation) | 10–20 kg per hectare per application (mature trees) | Every 1–2 weeks from bud burst to early autumn; set the annual total from leaf and soil tests |
| Orchards & large trees | Deep root feeding (hole method) | Young trees (1–3 years): 50–100 g per tree. Mature trees: 200–500 g per tree. Divide the amount between 4–8 holes, 15–30 cm deep, spaced around the drip line — never against the trunk or all in one hole. | Early spring and again in early summer; water in thoroughly straight after |
The commercial rates in this table are indicative only and have not been verified against the specific manufacturer’s label for this product. Confirm crop suitability, concentration, application volume and seasonal totals with the product label, a qualified agronomist and, where appropriate, soil and leaf tests before use. Before treating a whole block, test a foliar spray on a small area and check for leaf scorch after 2–3 days. Avoid foliar spraying in hot conditions, and do not tank-mix with calcium-based products such as calcium nitrate unless compatibility has been confirmed, as phosphate may precipitate and block nozzles or drippers.
For a more detailed fertigation plan, use our smart planner tool.
Other NPK Blends for Specific Growth Stages
Our range of specialised NPK blends tailored to different growth stages and plant needs.
- ●NPK 12-12-36: Ideal for boosting fruit size and taste during the flowering and fruiting stages.
- ●NPK 10-52-10: High in phosphorus, perfect for root and shoot development in young or stressed plants.
Why Australian Gardeners Trust Our Fertilisers
- ●Optimised for local climates: Tailored to Australia’s diverse conditions, from coastal gardens to arid farms.
- ●Eco-friendly and sustainable: Maximises plant health while minimising environmental impact.
- ●Cost-effective: Highly concentrated formulas mean more value per bag.
Frequently Asked Questions
How often should I apply NPK fertiliser?
Can I use NPK fertiliser for all plants?
Can I mix it stronger for faster results?
What size bags do you offer?
Shop NPK 20-20-20 Fertiliser Today
From a few pots on the balcony to broadacre paddocks, NPK 20-20-20 gives your plants a complete, balanced feed in every application. Explore our range of NPK blends.
Please quote us npk fertilizer
1. The fertilizer should be of European origin and contain 20% nitrogen (N), 20% phosphorus (P2O5), and 20% potassium (K2O2).
2. The fertilizer should be in granular (powder) form and fully soluble in water.
3. It should be free of any lumps or solid masses, and its moisture content should not exceed 0.5%.
4. It should be free of impurities such as chloride and other substances harmful to plants.
5. It should be packaged by the company in moisture-resistant, lined plastic bags, weighing 25 kg per bag, with a clear label and the Ministry of Agriculture’s seal.
6. The production date should not be before 2025, and it should have a shelf life of 3 years.
The contractor or the police must submit a sealed sample weighing no less than 10 kg.
Note that the sample will be opened for evaluation.
Hi there,
We have sent you an email from info@greenpick.au. Please be in touch with our team.
Thanks
Orchids how many gram perlite
Hi Tai,
For a more detailed advise please use our Fertigation tool here:
https://greenpick.com.au/fertigation-planner/
But as a general advice, you can use 10g in 10L water weekly, or the same ratio in different water volumes.
how much for 1000KG (1 TON)
Hi there,
We will send you an email from info@greenpick.com.au. Please be in touch with our team.
Thanks
Hi, I received the 500g pack this morning. Very excited to try it on my curry leaf plants. I have 3 in pots and looks a bit weathered but I see some new growth starting. Probably just waking up after our winter here in Hobart. We are starting to get warm days now. Can you advise the dosage to start off with for these 3 potted ones? Thanks.
Hi! 🌿 Great to hear you’re seeing new growth! For potted curry leaf plants just waking up, I’d start very gently with about 2-3g per litre of water. You can also pop your details into our Fertigation Planner for a better recommendation: https://greenpick.com.au/fertigation-planner/
Thank you for the reply. I am just preparing a mix of 5g to 2lts water.
Do we need to use cooled boiled water or can we use tap water?
Tap water is fine! 🌿 Just use room-temperature, and let it sit if it’s chlorinated.
Hi the recommended dose of 5g per one litre seems very high – and would give a ppm of 1000 rather than the optimal 100ppm.. Should this be 5g per ten litres?
Yes, you are right a typo. We fixed it.