Consumer advocacy teardown
Epsom Salts alternative & active ingredient dupe
Stop paying £6.50 for Westland. The bulk active is Magnesium sulphate heptahydrate (Epsom salts) — 59% less per working litre than a typical pack.
- Active
- Magnesium sulphate heptahydrate
- CAS
- 10034-99-8
- Dupe
- Magnesium sulphate heptahydrate (Epsom salts)
- Saving
- 59% / 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 1.5 kg box pack of Westland Epsom Salts is about £6.50 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: Greener leaves and better flowers; and Corrects magnesium deficiency in tomatoes and citrus.
The catch: The garden-centre box is agricultural Epsom salts with a picture of a tomato. MgSO4·7H2O is a commodity desiccant and bath salt. Buy it by the 5 kg bag, not 1.5 kg at a time. This is not BetterYou magnesium oil (that is chloride).
- “Greener leaves and better flowers”
- “Corrects magnesium deficiency in tomatoes and citrus”
Proprietary Blend & Dosage Breakdown
The labelled active is Magnesium sulphate heptahydrate at 100%. Everything else in the pack is none (crystals).
Even when the pack is sold as “pure” or ready-to-use, the dose that actually does the work is Magnesium sulphate heptahydrate. The rest is how they get it into a bottle you will pick up.
Branded working strength is whatever comes out of the bottle. The bulk alternative is 100% Magnesium sulphate heptahydrate (Epsom salts), mixed to 10 g/L as a foliar drench; 20 g/m² on soil.
- Labelled active
- Magnesium sulphate heptahydrate
- 100%
- Carrier
- None (crystals)
- Retail pack
- 1.5 kg box · £6.50
The Active Chemical Alternative (Dupe Stack)
The dupe stack is Magnesium sulphate heptahydrate (Epsom salts) at 100% bulk. Indexed as CAS 10034-99-8, formula MgSO4·7H2O. Buy it as 5 kg for about £8.99 from Amazon UK.
Working strength: 10 g/L as a foliar drench; 20 g/m² on soil. Indicative cost £0.02 per diluted litre — 59% 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.
- Food/technical grade crystals. Dissolve 10 g in 1 litre for a foliar feed, or broadcast 20 g/m² around hungry tomatoes and water in.
- 5 kg is more than three Westland boxes. Store dry — it cakes.
- This corrects magnesium. It is not a complete fertiliser and it is not a medicine.
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
Magnesium sulphate heptahydrate (Epsom salts)
- Concentrate
- 50 g
- grams of solid
- Water
- 5 L
- carrier volume
- Batch cost
- £0.09
- 5 L working solution
- Saved vs retail
- £0.13
- 59% · retail £0.22
Estimated coverage at the listed rate: 25 m².
Side-by-Side Price & Potency Comparison
Head-to-head comparison
| Measure | Retail brandedWestland | Raw active dupeDupeStack |
|---|---|---|
| Product | Epsom SaltsAmazon UK search — listing, not a confirmed seller | Magnesium sulphate heptahydrate (Epsom salts) |
| Pack / unit | 1.5 kg box · £6.50 | 5 kg · £8.99 |
| Active | Magnesium sulphate heptahydrate at 100%Carrier: None (crystals) | 100% bulkMgSO4·7H2O |
| CAS number | Not disclosed on pack | 10034-99-8 |
| Working strength | Ready-to-use pack | Dilute 10 g/L as a foliar drench; 20 g/m² on soil |
| Cost per litre | £6.50 / pack | £0.02 / L mixed from bulk |
| Headline saving | Baseline | 59% cheaper |
| COSHH / PPE | Follow the branded SDS | Gloves. Chemical-resistant gloves (nitrile or neoprene) |
Active ingredient and cheaper alternative — FAQ
What is the active ingredient in Westland?
Westland Epsom Salts is labelled as Magnesium sulphate heptahydrate at 100%. The carrier is None (crystals). Pack size: 1.5 kg box. The bulk equivalent we index is Magnesium sulphate heptahydrate (Epsom salts) (CAS 10034-99-8).
Is Magnesium sulphate heptahydrate (Epsom salts) safe on lawns?
Used at the listed working strength (10 g/L as a foliar drench; 20 g/m² on soil), 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 Westland Epsom Salts?
Yes. The bulk equivalent is Magnesium sulphate heptahydrate (Epsom salts) (CAS 10034-99-8). Indicative saving 59% per working litre versus a typical £6.50 pack. Working strength: 10 g/L as a foliar drench; 20 g/m² on soil. Live shop prices move.
How do you mix the Epsom Salts dupe stack?
Food/technical grade crystals. Dissolve 10 g in 1 litre for a foliar feed, or broadcast 20 g/m² around hungry tomatoes and water in. 5 kg is more than three Westland boxes. Store dry — it cakes. This corrects magnesium. It is not a complete fertiliser and it is not a medicine.
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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DIY stack · 59% / L vs branded
£16.50indicative kit · Amazon cannot add a mixed search kit as one basket