Lawn & garden
SB Plant Invigorator & Bug Killer dupe
Why pay around £14.99 for SB? The bulk active is Horticultural potassium soft soap — 53% less per working litre than a typical shelf pack.
From the retail pack to the active and the mix
1 · Retail
SB Plant Invigorator & Bug Killer
500 millilitres · £14.99 typical snapshot
Water and chelating agents
2 · Active
Foliar urea and alkyl surfactants
5% on the label
57-13-6 / 61790-44-1
Bulk Horticultural potassium soft soap
3 · Mix
10 ml soap + 5 g urea per litre
£0.14 per working litre · 53% less than the shelf pack
- Active
- Foliar urea and alkyl surfactants
- CAS
- 57-13-6 / 61790-44-1
- Dupe
- Horticultural potassium soft soap
- Saving
- 53% / 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
“Physical pest control for aphids, whitefly, spider mites and mealybugs”
The chemical reality
Dilute foliar urea plus a potassium fatty-acid soap that smothers soft-bodied insects. A 500 ml bottle at 10 ml/L makes about 50 litres; the same working spray from bulk soap and urea is pence per litre.
Active vs filler
5% Foliar urea and alkyl surfactants · 95% carrier / filler — Water and chelating agents
- Typical retail
- £14.99
- 500 millilitres
- Estimated active cost
- £0.34
- Scaled from bulk £13.50 / 1 litre soap (plus 1 kg urea in the stack)
- Indicative markup
- 44.4×
- Snapshot maths, not a live shop price
The Marketing Claim & The Catch
A 500 millilitres pack of SB Plant Invigorator & Bug Killer typically retails around £14.99 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: Physical pest control for aphids, whitefly, spider mites and mealybugs; and Foliar nutrition while checking powdery mildew.
The catch: Dilute foliar urea plus a potassium fatty-acid soap that smothers soft-bodied insects. A 500 ml bottle at 10 ml/L makes about 50 litres; the same working spray from bulk soap and urea is pence per litre.
- “Physical pest control for aphids, whitefly, spider mites and mealybugs”
- “Foliar nutrition while checking powdery mildew”
Proprietary Blend & Dosage Breakdown
The labelled active is Foliar urea and alkyl surfactants at 5%. Everything else in the pack is water and chelating agents.
At 5% 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 100% Horticultural potassium soft soap, mixed to 10 ml soap + 5 g urea per litre.
- Labelled active
- Foliar urea and alkyl surfactants
- 5%
- Carrier
- Water and chelating agents
- Retail pack
- 500 millilitres · £14.99
The Active Chemical Alternative (Dupe Stack)
The dupe stack is Horticultural potassium soft soap at 100% bulk. Indexed as CAS 57-13-6 / 61790-44-1. Buy it as 1 litre soap (plus 1 kg urea in the stack) for around £13.50 from Amazon UK.
Working strength: 10 ml soap + 5 g urea per litre. Indicative cost £0.14 per diluted litre — 53% 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.
- Mix 10 ml of potassium soft soap into 1 litre of warm water in a trigger sprayer, then dissolve 5 g of soluble urea.
- Spray both leaf faces in the morning. Physical smother — repeat after rain. Avoid hot sun on thin foliage.
- 1 litre of soap at 10 ml/L makes 100 litres of spray (use about 500 g of the urea bag).
- Do not mix with foliar copper or strong oxidisers.
Dilution recipe
1 L working batch
Working strength 10 ml soap + 5 g urea per litre. Educational estimate from the listed ratio — check the SDS before you mix.
Chemical
10 millilitres
Horticultural potassium soft soap
Water
0.99 litres
Carrier / diluent
1% concentrate · 99% 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 brandedSB | Raw active dupeDupeStack |
|---|---|---|
| Product | Plant Invigorator & Bug KillerAmazon UK search — listing, not a confirmed seller | Horticultural potassium soft soap |
| Pack / unit | 500 millilitres · £14.99 | 1 litre soap (plus 1 kg urea in the stack) · £13.50 |
| Active | Foliar urea and alkyl surfactants at 5%Carrier: Water and chelating agents | 100% bulk— |
| CAS number | Not disclosed on pack | 57-13-6 / 61790-44-1 |
| Working strength | Ready-to-use pack | Dilute 10 ml soap + 5 g urea per litre |
| Cost per litre | £29.98 / L typical pack | £0.14 / L mixed from bulk |
| Headline saving | Baseline | 53% cheaper |
| COSHH / PPE | Follow the branded SDS | Gloves. Chemical-resistant gloves (nitrile or neoprene)Eye protection. Indirect-vent splash goggles — not ordinary spectacles |
Active ingredient and cheaper alternative — FAQ
What is the active ingredient in SB?
SB Plant Invigorator & Bug Killer is labelled as Foliar urea and alkyl surfactants at 5%. The carrier is Water and chelating agents. Pack size: 500 millilitres. The bulk equivalent we index is Horticultural potassium soft soap (CAS 57-13-6 / 61790-44-1).
Is Horticultural potassium soft soap safe on lawns?
Used at the listed working strength (10 ml soap + 5 g urea per litre), 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 SB Plant Invigorator & Bug Killer?
Yes. The bulk equivalent is Horticultural potassium soft soap (CAS 57-13-6 / 61790-44-1). Indicative saving 53% per working litre versus a pack that typically retails around £14.99. Working strength: 10 ml soap + 5 g urea per litre. Live shop prices move.
How do you mix the Plant Invigorator & Bug Killer dupe stack?
Mix 10 ml of potassium soft soap into 1 litre of warm water in a trigger sprayer, then dissolve 5 g of soluble urea. Spray both leaf faces in the morning. Physical smother — repeat after rain. Avoid hot sun on thin foliage. 1 litre of soap at 10 ml/L makes 100 litres of spray (use about 500 g of the urea bag). Do not mix with foliar copper or strong oxidisers.
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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£22.50Save 53% / L
Indicative DIY stack