From 14p a square metre, if your clay is the right kind
One pass over a lawn costs 14p to 26p per square metre, depending on the bottle. Money well spent on clay that falls apart in water, or a lawn you cannot dig. Wasted on compaction or poor drainage, and we would rather you kept it. A crumb in a glass of water tells you which you have.
£19.99 1 litre, 100 m² at one pass
Choose Liquid Gypsum★★★★★ Shop rated 4.95/5 from 513 reviews. Free UK delivery over £40. Dispatched in 1 to 2 working days.
- The cost per square metre is small. The question is whether your soil is the kind it works on.
- Most gardens need less than they expect: a 50 m² lawn takes 500 ml for one feed.
- The 5 litre is for the full clay programme: a 50 m² lawn uses 4.5 litres, and it ships free.
What each bottle covers
| Bottle | Price | One feed covers | Full clay programme covers | Free delivery |
|---|---|---|---|---|
| 500 ml | £12.99 | 50 m² (26p per m²) | 5 m² | No |
| 1 litre | £19.99 | 100 m² (20p per m²) | 11 m² | No |
| 5 litres | £72.99 | 500 m² (15p per m²) | 55 m² | Yes |
| 2 × 5 litres | £135.00 | 1,000 m² (14p per m²) | 110 m² | Yes |
Feed: 10 ml per litre of water, 1 litre per m², autumn or spring. Clay programme: 15 ml per litre, fortnightly for three months from early autumn, then about every three years. Under £40 pays £3.00 delivery. Prices 27 Oct 2026. Other sizes: the calculator.
Worth it, or keep your money
| Worth it | Keep your money |
|---|---|
| The crumb clouds the glass | The crumb stays whole and the water stays clear |
| A clay lawn you cannot dig | A screwdriver will not go in: packed soil, so aerate |
| A soil test shows low calcium with neutral or high pH | A filled hole is still full next day: drainage |
| You want calcium without raising pH | Acid soil short of calcium: lime is cheaper and right |
The cheapest step is the test. A crumb, a screwdriver and a hole cost nothing: all three on the clay lawns page, or take the two-minute test.
Common questions
Which size for a 50 m² lawn?
One feed: the 500 ml. Autumn and spring: the 1 litre. The full clay programme uses 4.5 litres: the 5 litre, delivered free. The 5 litre is cheaper per litre, but only if you will use it.
Do I have to repeat it every year?
Not on most gardens. On heavy clay, about every three years. As a feed, stop when a soil test says calcium is fine.
Lime is cheaper. Why not use that?
If your soil is acid and short of calcium, do. Gypsum is for soil that is already neutral or alkaline, where lime would push pH too high, and for clay that falls apart in water.
What about the clear "liquid gypsum" products?
About a third of the calcium per litre, so more per square metre. See gypsum vs calcium thiosulfate.
Test the crumb first
If the water clouds, work out your area and buy the size that covers it, and no more.
£19.99 1 litre · 5 litres £72.99, free delivery
Free UK delivery over £40. Packed and posted from Stockport. Shake hard before every use.