Lawn & garden
Westland Sulphate of Ammonia dupe
Why pay around £7.50 for Westland? The bulk active is Agricultural ammonium sulphate 21% N — 64% less per working litre than a typical shelf pack.
From the retail pack to the active and the mix
1 · Retail
Westland Sulphate of Ammonia
1.5 kg box · £7.50 typical snapshot
None (prills)
2 · Active
Ammonium sulphate
21% on the label
7783-20-2(NH4)2SO4
Bulk Agricultural ammonium sulphate 21% N
3 · Mix
35 g/m²
£0.03 per working litre · 64% less than the shelf pack
- Active
- Ammonium sulphate
- CAS
- 7783-20-2
- Dupe
- Agricultural ammonium sulphate 21% N
- Saving
- 64% / 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.
Label teardown
What the pack promises versus what the label chemistry actually is.
The marketing claim
“Quick greening nitrogen for lawns, brassicas and leafy crops”
The chemical reality
21% nitrogen as ammonium sulphate. The cardboard box is a portioned sack of a fertiliser merchants sell in 25 kg lots. It greens grass. It also acidifies — do not pile it on chalk-hating stone paths.
Active vs filler
21% Ammonium sulphate · 79% carrier / filler — None (prills)
- Typical retail
- £7.50
- 1.5 kg box
- Estimated active cost
- £1.08
- Scaled from bulk £18.00 / 25 kg
- Indicative markup
- 6.9×
- Snapshot maths, not a live shop price
The Marketing Claim & The Catch
A 1.5 kg box pack of Westland Sulphate of Ammonia typically retails around £7.50 in lawn & garden. That is a UK shelf-price snapshot for the maths on this page — not a live shop quote or a manufacturer RRP. Listings, sizes and deals move. The marketing line is that you are buying a finished lifestyle product, not a weighed chemical.
On the pack: Quick greening nitrogen for lawns, brassicas and leafy crops; and Acidifying feed for lime-hating plants.
The catch: 21% nitrogen as ammonium sulphate. The cardboard box is a portioned sack of a fertiliser merchants sell in 25 kg lots. It greens grass. It also acidifies — do not pile it on chalk-hating stone paths.
- “Quick greening nitrogen for lawns, brassicas and leafy crops”
- “Acidifying feed for lime-hating plants”
Proprietary Blend & Dosage Breakdown
The labelled active is Ammonium sulphate at 21%. Everything else in the pack is none (prills).
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 21% Agricultural ammonium sulphate 21% N, mixed to 35 g/m².
- Labelled active
- Ammonium sulphate
- 21%
- Carrier
- None (prills)
- Retail pack
- 1.5 kg box · £7.50
The Active Chemical Alternative (Dupe Stack)
The dupe stack is Agricultural ammonium sulphate 21% N at 21% bulk. Indexed as CAS 7783-20-2, formula (NH4)2SO4. Buy it as 25 kg for around £18.00 from Amazon UK.
Working strength: 35 g/m². Indicative cost £0.03 per diluted litre — 64% 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. Avoid breathing dust. Broadcast 35 g/m² on a dry lawn, then water in. Keep off ponds.
- A 25 kg sack covers about 700 m² at 35 g/m². That is more than sixteen 1.5 kg boxes.
- Do not mix with lime in the same pass. Store dry.
Dilution recipe
5 L sprayer
Working strength 35 g/m². Educational estimate from the listed ratio — check the SDS before you mix.
Chemical
3,500 grams
Agricultural ammonium sulphate 21% N
Water
5 litres
Carrier / diluent
0% concentrate · 100% water by working volume (solids are dissolved into the water share).
Required PPE
Loading calculator…
Side-by-Side Price & Potency Comparison
Head-to-head comparison
| Measure | Retail brandedWestland | Raw active dupeDupeStack |
|---|---|---|
| Product | Sulphate of AmmoniaAmazon UK search — listing, not a confirmed seller | Agricultural ammonium sulphate 21% N |
| Pack / unit | 1.5 kg box · £7.50 | 25 kg · £18.00 |
| Active | Ammonium sulphate at 21%Carrier: None (prills) | 21% bulk(NH4)2SO4 |
| CAS number | Not disclosed on pack | 7783-20-2 |
| Working strength | Ready-to-use pack | Dilute 35 g/m² |
| Cost per litre | £7.50 / pack | £0.03 / L mixed from bulk |
| Headline saving | Baseline | 64% 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 Westland?
Westland Sulphate of Ammonia is labelled as Ammonium sulphate at 21%. The carrier is None (prills). Pack size: 1.5 kg box. The bulk equivalent we index is Agricultural ammonium sulphate 21% N (CAS 7783-20-2).
Is Agricultural ammonium sulphate 21% N safe on lawns?
Used at the listed working strength (35 g/m²), 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 Sulphate of Ammonia?
Yes. The bulk equivalent is Agricultural ammonium sulphate 21% N (CAS 7783-20-2). Indicative saving 64% per working litre versus a pack that typically retails around £7.50. Working strength: 35 g/m². Live shop prices move.
How do you mix the Sulphate of Ammonia dupe stack?
Wear gloves. Avoid breathing dust. Broadcast 35 g/m² on a dry lawn, then water in. Keep off ponds. A 25 kg sack covers about 700 m² at 35 g/m². That is more than sixteen 1.5 kg boxes. Do not mix with lime in the same pass. Store dry.
DupeStack provides chemical concentration data and educational mixing guides only. Wellness pages compare food supplements, not medicines or prescribed treatments. Always review the supplier Safety Data Sheet (SDS) and comply with UK Health and Safety Executive (HSE) and COSHH regulations when handling concentrated substances. Mixing and storage are at your own risk. Some links are affiliate advertisements (Amazon Associates, eBay Partner Network, and Awin when those programmes are live). Commissions do not change listed concentrations or calculator output.
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£32.00Save 64% / L
Indicative DIY stack