← Liquid gypsum FAQ

Why is my garden soil sticky and heavy?

Because it is clay. The particles are small enough to hold water films between them, and that is texture, which you cannot change. Structure is the part you can.

Texture and structure are different things

Texture is the proportion of sand, silt and clay in your soil. It was set by the geology under your garden and by whatever was deposited on top of it, and nothing you add in domestic quantities shifts it. Turning a clay soil into a loam by adding sand would take a volume of sand comparable to the volume of soil, which is why the advice to add a bag of grit does nothing.

Structure is how those particles are grouped. The same clay can behave as a sticky, airless mass or as workable crumbs with pores between them, depending entirely on whether something is binding the particles together. Structure is the part that responds to management, and it is where all the useful effort goes.

Why clay feels the way it does

A clay particle is under two microns across, hundreds of times smaller than a grain of sand. Pack those into a handful of soil and the internal surface area is vast. Water spreads as thin films across all of it and clings there, which is why clay stays wet long after sandy soil has drained and why it smears when you work it. The same surface area is why clay holds nutrients so well. Heavy soil is fertile soil, generally speaking, once you can work with it.

What actually improves it

Organic matter, applied repeatedly and over years. Compost, leaf mould and well-rotted manure feed the fungi and bacteria whose threads and gums bind particles into crumbs, and those crumbs are what give clay air spaces and drainage. Mulching keeps the surface covered and the worms working near the top.

Just as important is what you stop doing. Digging or walking on clay while it is wet destroys structure faster than anything rebuilds it. Boards to spread your weight, permanent beds and paths, and patience through the wet months all count for more than any product.

Where liquid gypsum fits

Gypsum supplies calcium and sulphur, and calcium is one of the things that bridges clay plates into crumbs. On clay that disperses, that matters and the effect is quick. On ordinary non-dispersive clay, which is most British garden soil, the structural benefit is modest and the honest answer is that organic matter does the lasting work. It is worth knowing which you have before spending anything.

Dr Forest Liquid Gypsum is micronised natural calcium sulphate suspended in fulvic acid, with no synthetic dispersants, and there is a dilution calculator if you want to work out quantities first.