Gypsum job or fork job? Three checks tell you.
A lawn that puddles has one of three problems: packed-down soil, clay that falls apart in water and seals over, or water with nowhere to go. Liquid Gypsum only helps with the second. Watered on through the grass, no lifting.
£19.99 1 litre, 100 m² of lawn
Choose Liquid Gypsum★★★★★ Shop rated 4.95/5 from 513 reviews. Free UK delivery over £40. Dispatched in 1 to 2 working days.
- Not an aerator. Soil packed down by feet and mowers needs a hollow-tine fork, the kind that pulls out plugs.
- Works on clay that falls apart in water, keeping the surface open so rain soaks in.
- September to November first, March to April second. Never on frozen or waterlogged ground.
Three checks before you buy
- Crumb in a glass. A dry, pea-sized crumb in rainwater overnight. Cloudy water: gypsum has a job. Clear: it does not. Full test here.
- Screwdriver. Push it into moist lawn. Stops after an inch or two: packed-down soil. Fork first.
- Hole. Dig a spade deep, fill twice. Still full next morning: drainage, not a bottle.
What you see, what to use
| What you see | Cause | Right tool |
|---|---|---|
| Puddles on worn paths, screwdriver stops | Packed-down soil | Aerate, brush in sharp sand. Gypsum after, if the crumb clouds |
| Shiny skin after rain, crumb clouds | Clay that falls apart in water | Liquid Gypsum, autumn programme |
| Wet all winter, hole stays full | Nowhere for water to go | Land drain or soakaway. Not gypsum |
| Drains fine, want calcium without lifting turf | Feeding | Liquid Gypsum, 10 ml per m² |
Many clay lawns need both: aerate first, then water gypsum on so the holes carry it down. A bag of "clay breaker" that says calcium sulphate is gypsum under another name.
Rates and cost
| Pack | Price | Feed covers | Programme covers |
|---|---|---|---|
| 500 ml | £12.99 | 50 m² | 5 m² patch |
| 1 litre | £19.99 | 100 m² | 11 m² patch |
| 5 litres | £72.99 | 500 m² | 55 m² |
| 2 × 5 litres | £135.00 | 1,000 m² | 110 m² |
Feed: 10 ml per litre of water, 1 litre per m², once or twice a year. Programme: 15 ml per litre fortnightly for three months, then every three years or so. Shake 30 seconds. Treat only the area that puddles. Cost per m²: price page; your numbers: calculator.
Common questions
Will it stop the puddles on my lawn?
Only if they come from clay sealing the surface. Cloudy glass: run the autumn programme. Clear glass: packed soil or drainage, and gypsum will not shift them.
Do I still need to aerate?
If the screwdriver stops, yes. Aerate first, then water gypsum on if the crumb test also says yes.
Lime or gypsum for moss?
Neither. Moss is shade, wet and packed soil.
Safe for kids and dogs?
Off the lawn while you apply, back on once it has soaked in. Details on the pets and children page.
Watered on, no lifting the turf
If the glass went cloudy, this is the job. 10 ml per m² to feed, 15 ml per m² fortnightly through autumn.
£19.99 1 litre · 5 litres £72.99
Free UK delivery over £40. Dispatched in 1 to 2 working days. Packed and sent from Stockport.