Gypsum (Calcium Sulphate) is a high-purity, pH-neutral source of calcium and sulphur — essential for situations where you need to top up calcium without shifting your soil's pH. If anything, it carries a very mild acidifying quality, making it a smart choice for mid-season amendments, coco-based mixes, or any blend that isn't inherently acidic and doesn't need further alkalinity.
Providing approximately 20% calcium and 16% sulphur, gypsum supports strong cell wall development and enzyme function across all growth stages. It's particularly well suited to acidic-soil-loving plants that still need adequate calcium supply — a combination that's hard to achieve with liming agents.
We stock white, graded gypsum with an approximate maximum particle size of 2–3 mm, with the majority being fine powder. Not all gypsum is equal — cheap sources are often recycled from gyprock particle board or pulled from low-quality mines where seam wall material ends up mixed with the extract. Both are inferior due to potential contamination and reduced purity.
