Three boxes, three jobs
Spring lawn aisles sell ‘feed and weed and moss killer’ as one miracle. Split the chemistry. Iron blackens moss. Nitrogen greens grass. Selective auxins hit daisies. Glyphosate kills whatever is green — including the turf.
If the lawn is yellow and thin, weigh a nitrogen salt. If it is a green carpet of moss, you need ferrous sulphate and then scarify — not a bigger handful of Growmore. If the soil is sour and brassicas sulk, that is garden lime (calcium carbonate) — the opposite of iron, and it will lock iron for camellias.
Ferrous sulphate — moss, not a shrub tonic
Evergreen Complete 4-in-1 is built around ferrous sulphate heptahydrate. It blackens moss in days and can rust-stain pale stone and clothes. Mo Bacter packages an iron moss story with a bacterial marketing layer — still not sequestered iron for rhododendrons.
Vitax sequestered iron (Fe-EDDHA) is a chelate for lime-locked shrubs. It will not substitute for lawn sand. Keep both irons off sandstone you care about; they drip orange.
Sulphate of ammonia — green-up, not moss death
Westland sulphate of ammonia is 21% nitrogen as (NH4)2SO4. It is a merchant’s salt in a 1.5 kg box. It greens leafy growth and acidifies slightly. It is not a 7-7-7 complete feed and it is not a moss killer.
Weigh per square metre from the teardown. Do not pile it against chalk-hating paving. Water in; keep off ponds.
Weeds in grass vs moss vs paths
Daisies and dandelions in established turf → mecoprop-P plus dicamba (Doff) or the current Weedol Lawn three-way (MCPA, fluroxypyr, clopyralid). Moss → iron. Bare path weeds → glyphosate or pelargonic — see the weedkiller guide. Do not spray Pathclear on the lawn and call it a moss treatment.
FAQ
- Will sulphate of ammonia kill moss?
- Not reliably. Ammonium sulphate is a quick nitrogen salt that greens grass and acidifies a little. Moss on a lawn is usually a ferrous sulphate / lawn-sand job (or shade and drainage). See the Evergreen and Mo Bacter teardowns.
- Is Evergreen Complete just Growmore with moss killer?
- No. Growmore is inorganic 7-7-7. Evergreen-style 4-in-1 boxes lead with ferrous sulphate to blacken moss, plus a feed and often a herbicide story. Read the SDS — the iron is the moss chemistry.
- Can I use glyphosate on moss in the lawn?
- It will brown the grass too. Pathclear is for hard surfaces. Daisies in turf are mecoprop-P plus dicamba (Doff) or MCPA/fluroxypyr/clopyralid (current Weedol Lawn). Moss is iron, not glyphosate.
More lawn & garden guides
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Lawn and plant food labels decoded: NPK without the brand box
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Weedkillers decoded: glyphosate vs triclopyr — paths, brambles and lawn
Lawn guide
Garden tonics decoded: seaweed, chelated iron, Epsom and rooting powder
Lawn guide
Garden pests and disease: fungicides vs insecticides — not weedkillers
Related teardowns
Live stacks this guide points at — mix maths and DIY affiliate links on each page.
Lawn & garden
Evergreen Complete 4-in-1 Lawn Feed & Moss Killer
Evergreen
- Retail pack
- £24.00100 m² box
- Raw active
- Agricultural soluble iron(II) sulphate heptahydrate7782-63-0
The moss-blackening punch is ferrous sulphate — the same agricultural iron used on bowling greens. The 4-in-1 box is mostly filler, NPK dust and a brand. Buy the salt.
Lawn & garden
Garden Lime
Westland
- Retail pack
- £8.004 kg
- Raw active
- Agricultural ground limestone (calcium carbonate / dolomite lime)1317-65-3
Westland’s 4 kg box is agricultural lime: limestone calcium carbonate (CAS 1317-65-3) with dolomite (CAS 16389-88-1) — not hydrated lime, not ferrous sulphate, and not a weedkiller. A 25 kg ag-lime sack is the same pH-up salt. Test the soil first; keep it off rhododendrons.
Lawn & garden
Organic Lawn Moss Killer & Fertiliser
Mo Bacter
- Retail pack
- £38.0020 kg bag
- Raw active
- Sulphate of potash (0-0-50)7778-80-5
The moss dies because of high potash, not a magic organic patent. Sulphate of potash (0-0-50) supplies the same K2O without iron staining; a cheap Bacillus or compost-tea inoculant does the digestion step. A 20 kg 5-5-20 bag is mostly filler next to 10 kg of 50% K2O.
Lawn & garden
Sulphate of Ammonia
Westland
- Retail pack
- £7.501.5 kg box
- Raw active
- Agricultural ammonium sulphate 21% N7783-20-2
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.
Lawn & garden
Sequestered Iron Plant Tonic
Vitax
- Retail pack
- £6.9980 g (4 × 20 g sachets)
- Raw active
- Fe-EDDHA 6% chelated iron (plus a pinch of Mg/Mn if you want the full tonic)16455-61-1
This is not ferrous sulphate (that is Evergreen moss killer) and it will not blacken a pale patio the same way. EDDHA/EDTA iron stays available on chalky soil. Four 20 g sachets are a tiny bag of the 6% chelate sold in 250 g tubs to nurseries.
Lawn & garden
Growmore Garden Fertiliser
Growmore
- Retail pack
- £9.504 kg
- Raw active
- Agricultural NPK 7-7-7 compound fertiliser66455-26-3
7-7-7 is a commodity NPK blend. The cardboard box is a portioned sack of agricultural compound fertiliser. Buy it by the 25 kg bag from a merchant, not 4 kg at a time from a garden centre.
Lawn & garden
Concentrated Lawn Weedkiller
Doff
- Retail pack
- £8.49200 millilitres
- Raw active
- Mecoprop-P 37.5 g/L + dicamba 4.675 g/L lawn concentrate16484-77-8 / 1918-00-9
Doff’s 200 ml lawn bottle is mecoprop-P at 37.5 g/L plus dicamba at 4.675 g/L — a selective auxin herbicide for turf, not glyphosate. Weedol LN Conc is the same pair. Current Weedol Lawn (MAPP 17599) is a different three-way — MCPA, fluroxypyr and clopyralid — see that teardown. A 1 L bottle of the mecoprop-P/dicamba formulation is the same working spray without the 200 ml garden-centre tax.
Lawn & garden
Lawn Weedkiller Concentrate
Weedol
- Retail pack
- £14.99500 millilitres
- Raw active
- MCPA 53.4 g/L + fluroxypyr 10.7 g/L + clopyralid 5.4 g/L lawn concentrate94-74-6 / 69377-81-7 / 1702-17-6
Current Weedol Lawn (MAPP 17599) is MCPA at about 53.4 g/L plus fluroxypyr 10.7 g/L and clopyralid 5.4 g/L — a three-way selective turf herbicide, not Doff’s mecoprop-P/dicamba pair and not Pathclear glyphosate. A 1 L amateur pack of that same three-way is the working spray without the 500 ml carton tax.
Lawn & garden
Pathclear Ready to Use Weedkiller
Weedol
- Retail pack
- £8.491 litre
- Raw active
- Glyphosate IPA salt concentrate 360 g/L38641-94-0
Pathclear RTU is glyphosate at about 0.46 g/L in a trigger bottle. The same working strength comes from 13 ml of 360 g/L glyphosate concentrate per litre of water — pennies per litre versus £8.49 for the branded RTU.
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