Consumer advocacy teardown
Miracle-Gro All Purpose Liquid Plant Food alternative & active ingredient dupe
Stop paying £6.00 for Miracle-Gro. The bulk active is Soluble NPK 20-20-20 (hydroponic grade) — 80% less per working litre than a typical pack.
- Active
- Soluble NPK (approx. 8-7-6)
- CAS
- 66455-26-3
- Dupe
- Soluble NPK 20-20-20 (hydroponic grade)
- Saving
- 80% / L
Saving is per litre of working-strength mix versus a typical pack price, not versus the DIY kit total. Shop prices move — always check the listing.
The Marketing Claim & The Catch
A typical 1 litre pack of Miracle-Gro All Purpose Liquid Plant Food is about £6.00 in lawn & garden. That is a snapshot, not a live Amazon price — listings, sizes and deals move. The marketing line is that you are buying a finished lifestyle product, not a weighed chemical.
On the pack: Instant feed for pots, beds and baskets; More blooms, greener leaves; and Mix with water and pour.
The catch: A dilute bottle of soluble NPK. Hydroponic 20-20-20 (or similar) powder is the same three numbers, un-dyed and un-marketed, at a gram per litre instead of a capful of coloured water.
- “Instant feed for pots, beds and baskets”
- “More blooms, greener leaves”
- “Mix with water and pour”
Proprietary Blend & Dosage Breakdown
The labelled active is Soluble NPK (approx. 8-7-6) at 21%. Everything else in the pack is water.
At 21% active, most of what you pay for is carrier and packaging. The brand is selling convenience, fragrance and a label — not a uniquely potent molecule.
Branded working strength is whatever comes out of the bottle. The bulk alternative is 60% Soluble NPK 20-20-20 (hydroponic grade), mixed to 1 g/L.
- Labelled active
- Soluble NPK (approx. 8-7-6)
- 21%
- Carrier
- Water
- Retail pack
- 1 litre · £6.00
The Active Chemical Alternative (Dupe Stack)
The dupe stack is Soluble NPK 20-20-20 (hydroponic grade) at 60% bulk. Indexed as CAS 66455-26-3, formula N + P2O5 + K2O. Buy it as 1 kg for about £12.00 from Amazon UK.
Working strength: 1 g/L. Indicative cost £0.01 per diluted litre — 80% below a typical branded pack on a per-litre basis, before you reuse leftover bulk.
Follow the mixing method and the supplier SDS. Wear the listed PPE. Do not mix incompatible oxidisers, acids or ammonia.
- Wear gloves when handling the powder. Avoid inhaling dust.
- Dissolve 1 g per litre of water for a general foliar/root feed (1 kg yields ~1,000 L).
- For hungrier tomatoes or baskets, 1.5–2 g/L. Flush pots monthly to avoid salt build-up.
- Do not exceed the rate — fertiliser burn is real.
- Store sealed and dry.
Mixing desk
Dilution calculator
Switch between filling a sprayer and covering a measured surface. Figures are educational estimates from the listed ratio — always check the SDS.
Formula
Soluble NPK 20-20-20 (hydroponic grade)
- Concentrate
- 5 g
- grams of solid
- Water
- 5 L
- carrier volume
- Batch cost
- £0.06
- 5 L working solution
- Saved vs retail
- £29.94
- 100% · retail £30.00
Estimated coverage at the listed rate: 20 m².
Side-by-Side Price & Potency Comparison
Head-to-head comparison
| Measure | Retail brandedMiracle-Gro | Raw active dupeDupeStack |
|---|---|---|
| Product | Miracle-Gro All Purpose Liquid Plant FoodAmazon UK search — listing, not a confirmed seller | Soluble NPK 20-20-20 (hydroponic grade) |
| Pack / unit | 1 litre · £6.00 | 1 kg · £12.00 |
| Active | Soluble NPK (approx. 8-7-6) at 21%Carrier: Water | 60% bulkN + P2O5 + K2O |
| CAS number | Not disclosed on pack | 66455-26-3 |
| Working strength | Ready-to-use pack | Dilute 1 g/L |
| Cost per litre | £6.00 / L typical pack | £0.01 / L mixed from bulk |
| Headline saving | Baseline | 80% cheaper |
| COSHH / PPE | Follow the branded SDS | Gloves. Chemical-resistant gloves (nitrile or neoprene)Ventilation. Use outdoors or with mechanical extraction |
Active ingredient and cheaper alternative — FAQ
What is the active ingredient in Miracle-Gro?
Miracle-Gro All Purpose Liquid Plant Food is labelled as Soluble NPK (approx. 8-7-6) at 21%. The carrier is Water. Pack size: 1 litre. The bulk equivalent we index is Soluble NPK 20-20-20 (hydroponic grade) (CAS 66455-26-3).
Is Soluble NPK 20-20-20 (hydroponic grade) safe on lawns?
Used at the listed working strength (1 g/L), the dupe is the same chemistry as the branded pack for lawns, beds and pots. That is not a blanket all-clear: read the supplier SDS, wear the listed PPE, keep acids away from hypochlorite, and follow UK HSE/COSHH rules. Wellness teardowns are supplements, not medicines.
Is there a cheaper alternative to Miracle-Gro All Purpose Liquid Plant Food?
Yes. The bulk equivalent is Soluble NPK 20-20-20 (hydroponic grade) (CAS 66455-26-3). Indicative saving 80% per working litre versus a typical £6.00 pack. Working strength: 1 g/L. Live shop prices move.
How do you mix the Miracle-Gro All Purpose Liquid Plant Food dupe stack?
Wear gloves when handling the powder. Avoid inhaling dust. Dissolve 1 g per litre of water for a general foliar/root feed (1 kg yields ~1,000 L). For hungrier tomatoes or baskets, 1.5–2 g/L. Flush pots monthly to avoid salt build-up. Do not exceed the rate — fertiliser burn is real. Store sealed and dry.
DupeStack provides chemical concentration data and educational mixing guides. Always review official manufacturer Safety Data Sheets (SDS) and comply with UK Health and Safety Executive (HSE) and COSHH regulations when handling concentrated substances. Some links on this site are affiliate links.
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- £9.504 kg
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DIY stack · 80% / L vs branded
£22.98indicative kit · Amazon cannot add a mixed search kit as one basket