Gypsum for lawns on heavy clay, with the autumn feed kit underneath
Autumn lawn feed with gypsum for lawns on heavy clay: alfalfa nitrogen, polyhalite potassium, and granulated gypsum to flocculate the surface. The feeding half is the same as the standard Autumn Lawn Kit; the third bag is there because gypsum for clay soil earns its place on clay and very little elsewhere.
Alfalfa Meal Pellets give low, slow, plant-based nitrogen for the end of the season. Polyhalite brings potassium with calcium, magnesium and sulphur. Granulated Gypsum supplies calcium and sulphur without shifting pH. On a clay that disperses and then sets hard, calcium is the mechanism that helps the particles hold together as crumbs. Our guide on how to amend clay soil explains how to check whether yours disperses before you spend on gypsum. What is in the kit: Alfalfa Meal Pellets, Polyhalite Fertiliser and Granulated Gypsum, a horticultural gypsum for turf and beds: 1.5 kg of each in the Small set, 4.5 kg, 4 kg and 4 kg in the Medium, and 9 kg of each in the Large. One caveat worth stating. There is no field trial comparing autumn with spring application of garden gypsum on turf. The case for the autumn timing is mechanism reasoning, and we would rather say so than dress it up as settled. Gypsum also does nothing for a soil that is simply compacted rather than dispersed. Each bag carries its own application rate; we have not set a combined rate for the kit. More in Lawn Care, Clay Soil and Bundles & Kits.
Pick a size on the product form. Each size is a full set of the named packs below, not a single bag.
- Small (1.5 kg each (4.5 kg total)): Alfalfa Meal Pellets: 1.5 kg; Polyhalite Fertiliser: 1.5 kg; Granulated Gypsum: 1.5 kg
- Medium (4.5 kg alfalfa + 4 kg polyhalite + 4 kg gypsum (12.5 kg total)): Alfalfa Meal Pellets: 4.5 kg; Polyhalite Fertiliser: 4 kg; Granulated Gypsum: 4 kg
- Large (9 kg each (27 kg total)): Alfalfa Meal Pellets: 9 kg; Polyhalite Fertiliser: 9 kg; Granulated Gypsum: 9 kg
Rates stay on each component listing. The size picker only changes how much of each pack you get.
Each is also sold on its own: Alfalfa Meal Pellets · Polyhalite Fertiliser · Granulated Gypsum
When gypsum for lawns belongs in the kit
- Gypsum for clay soil under turf that smears wet and sets hard dry
- Garden gypsum as a horticultural gypsum bag beside the autumn feed
- Autumn lawn feed on clay, without pretending gypsum is a feed
- Not for a sandy lawn, and not for compaction you can only spike out
Clay kit: feed plus granulated gypsum
- Same alfalfa and polyhalite as the standard autumn kit
- Third bag is granulated gypsum for clay
- Three rates, no combined NPK
Standard autumn kit, or liquid gypsum and wetting agent
- No clay: Autumn Lawn Kit is two bags
- Puddles and a hydrophobic surface: Liquid Gypsum and Wetting Agent, watered on together
Dr Forest packs this in Stockport. Three named bags. Made with organic ingredients; we do not call it certified organic.
Gypsum for lawns: calcium on dispersed clay, not a miracle on compaction
Gypsum (calcium sulphate) supplies calcium without raising pH, which is why it is the usual mineral on a clay that disperses. Calcium helps clay particles flocculate into crumbs (Shainberg et al., 1989). If the lawn is simply compacted by feet and machines, gypsum will not stand in for aeration.
We have not got a turf trial that settles autumn versus spring for garden gypsum. The alfalfa goes on in late August and the polyhalite and gypsum in autumn. Treat the gypsum timing as mechanism, not as a published turf result.
Granulated gypsum is the dry bag. Liquid gypsum is a different product and a different kit.
Calcium without a pH swing
Gypsum is calcium sulphate, not lime.
Flocculation, not magic
Dispersed clay can crumb; compacted clay still needs air.
Late August, then autumn
Alfalfa in late August; polyhalite and gypsum in autumn.
No combined rate
Three bags, three listings.
References
- Shainberg, I. et al. (1989). Use of gypsum on soils: a review. Advances in Soil Science, 9.
- Johnston, A.E. & Dawson, C.J. (2018). Polyhalite as a fertiliser. Proceedings 826, International Fertiliser Society.
How to use Autumn Lawn Kit for Clay Lawns
Confirm clay that smears. Put the alfalfa on in late August, at the lawn rate on its own page, so the last nitrogen goes on by the end of August. Apply the polyhalite and granulated gypsum in September to early October, while the grass is still growing, each at the rate on its own page. Three bags, three rates; gypsum is structure/S, not “more Ca” on top of polyhalite. Do not stack with lime.
Follow alfalfa, polyhalite and granulated gypsum on their own pages. Do not invent a combined handful for clay turf.
If the soil is packed rather than chemically dispersed, aerate. Gypsum will not replace a fork.
Polyhalite
Granulated gypsum
- Confirm it is clay that smears, not just a packed path.
- Feed bags: alfalfa and polyhalite at their rates.
- Gypsum: granulated gypsum at its rate.
- Puddling surface: look at Liquid Gypsum and Wetting Agent.
No clay: Autumn Lawn Kit. Liquid route: Liquid Gypsum and the wetting agent. Collection: Clay Soil.
Autumn Lawn Kit for Clay Lawns: questions
Both, as two jobs. Alfalfa and polyhalite feed. Granulated gypsum is the clay mineral.
The gypsum bag can be used as its listing says. This kit is merchandised for clay lawns.
Not if the only problem is compaction. Aerate.
The alfalfa goes on in late August, so the last nitrogen is down by the end of August. Polyhalite and gypsum go on in autumn. Gypsum timing on turf is mechanism reasoning, not a trial we can cite.
No.
Made with organic ingredients. We do not call it certified organic.
Stockport.
Different product. Puddling lawns often want Liquid Gypsum and Wetting Agent.
Here. This kit is three bags (alfalfa pellets and polyhalite to feed, granulated gypsum for the clay) in Small (1.5 kg each), Medium (4.5 kg alfalfa, 4 kg polyhalite, 4 kg gypsum) or Large (9 kg each) sets, packed in Stockport and posted to any UK address. If your lawn puddles after rain, look at Liquid Gypsum and Wetting Agent.
Yes. At today's prices (October 2026) every size costs about 10–12% less than buying the same products separately. The smallest size is £28.95 against £32.98 bought one by one, a saving of £4.03. Check each product page for current single prices.
Not in the bundle. The sizes are fixed: 1.5 kg each (4.5 kg total); 4.5 kg alfalfa + 4 kg polyhalite + 4 kg gypsum (12.5 kg total); 9 kg each (27 kg total). If you want different amounts, buy the products on their own pages and mix the sizes as you like.
Yes. Each one is sold on its own: Alfalfa Meal Pellets, Polyhalite Fertiliser, Granulated Gypsum.