{"product_id":"sulphur-soil-acidifier","title":"Sulphur Soil Acidifier | Lower Soil pH for Ericaceous Plants \u0026 Blueberries","description":"\u003cstyle\u003e\n  .drf-wrap *, .drf-wrap *::before, .drf-wrap *::after { box-sizing: border-box; margin: 0; padding: 0; }\n  .drf-wrap { font-family: 'Jost', sans-serif; font-weight: 400; color: #2c2c2c; font-size: 14px; line-height: 1.65; width: 100%; max-width: 100%; overflow: hidden; }\n  :root {\n    --drf-grn:        #1B3D2F;\n    --drf-grn-light:  #E8F0EB;\n    --drf-grn-mid:    #4a7a5e;\n    --drf-grn-dark:   #0F2A1F;\n    --drf-gold:       #C5A55A;\n    --drf-gold-light: #FAF7F0;\n    --drf-cream:      #F5F2EC;\n    --drf-border:     #d4cfc5;\n    --drf-muted:      #3A4A40;\n    --drf-white:      #FFFFFF;\n  }\n  .drf-wrap h2 { font-family: 'Cormorant Garamond', serif; font-weight: 400; font-size: 1.9em; color: var(--drf-grn); line-height: 1.25; margin-bottom: 0.5em; }\n  .drf-wrap h3 { font-family: 'Cormorant Garamond', serif; font-weight: 400; 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background: var(--drf-grn); color: #fff; border-color: var(--drf-grn); }\n  .drf-faq input:checked ~ .drf-faq-a { max-height: 900px; }\n\n  \/* ── REFS \u0026 SEPARATOR (200px hairline) ── *\/\n  .drf-refs { font-size: 0.78em; color: #888; line-height: 1.5; margin-top: 1.5em; padding-top: 0.8em; border-top: 1px solid var(--drf-border); }\n  .drf-refs ol { padding-left: 1.4em; margin: 0; }\n  .drf-refs li { margin-bottom: 0.3em; }\n  .drf-sep { border: none; border-top: 1px solid var(--drf-gold); width: 200px; margin: 1.8em auto; }\n\n  \/* ── TABLE ── *\/\n  .drf-wrap table { width: 100%; border-collapse: collapse; margin: 1em 0; font-size: 0.92em; }\n  .drf-wrap table th { background: var(--drf-grn); color: #fff; font-weight: 600; padding: 0.6em 0.8em; text-align: left; font-size: 0.85em; letter-spacing: 0.04em; }\n  .drf-wrap table td { padding: 0.55em 0.8em; border-bottom: 1px solid var(--drf-border); }\n  .drf-wrap table tr:nth-child(even) td { background: var(--drf-grn-light); }\n\n  \/* ── FIGURES \/ GRAPHS (v1.0 additions) ── *\/\n  .drf-fig { margin: 1.2em 0 1.4em; border: 1px solid var(--drf-border); border-top: 2px solid var(--drf-gold); background: var(--drf-white); padding: 1em 1em 0.8em; }\n  .drf-fig svg { width: 100%; height: auto; display: block; }\n  .drf-fig-cap { font-size: 0.8em; color: var(--drf-muted); line-height: 1.55; margin-top: 0.7em; }\n  .drf-fig-cap strong { color: var(--drf-grn); }\n\u003c\/style\u003e\n\u003cdiv class=\"drf-wrap\"\u003e\n\u003cdiv class=\"drf-tabs-wrap\"\u003e\n\u003cinput checked id=\"drf-su-tab1\" name=\"drf-su-tabset\" type=\"radio\"\u003e \u003cinput id=\"drf-su-tab2\" name=\"drf-su-tabset\" type=\"radio\"\u003e \u003cinput id=\"drf-su-tab3\" name=\"drf-su-tabset\" type=\"radio\"\u003e \u003cinput id=\"drf-su-tab4\" name=\"drf-su-tabset\" type=\"radio\"\u003e\n\u003cdiv class=\"drf-tab-labels\"\u003e\n\u003clabel for=\"drf-su-tab1\"\u003eOverview\u003c\/label\u003e \u003clabel for=\"drf-su-tab2\"\u003eThe Science\u003c\/label\u003e \u003clabel for=\"drf-su-tab3\"\u003eHow to Use\u003c\/label\u003e \u003clabel for=\"drf-su-tab4\"\u003eFAQ\u003c\/label\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-panels\"\u003e\n\u003c!-- ============ OVERVIEW ============ --\u003e\n\u003cdiv id=\"drf-su-panel1\" class=\"drf-panel\"\u003e\n\u003cdiv class=\"drf-badge-row\"\u003e\n\u003cdiv class=\"drf-badge drf-badge-green\"\u003e90% S + 10% Bentonite\u003c\/div\u003e\n\u003cdiv class=\"drf-badge drf-badge-gold\"\u003eLowers Soil pH\u003c\/div\u003e\n\u003cdiv class=\"drf-badge drf-badge-dark\"\u003eEricaceous \u0026amp; Blueberries\u003c\/div\u003e\n\u003cdiv class=\"drf-badge drf-badge-green\"\u003ePacked in Stockport\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch2\u003eSulphur soil acidifier — lower your soil pH the natural way\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eSulphur soil acidifier is elemental sulphur (S) that soil bacteria oxidise into sulphuric acid\u003c\/strong\u003e, which lowers soil pH so acid-loving, ericaceous (lime-hating) plants can take up iron and manganese properly. Ours is a sulphur-bentonite pastille — \u003cstrong\u003e90% elemental sulphur with 10% bentonite clay\u003c\/strong\u003e. Spread it dry with no dust, then the moment it gets wet the bentonite swells and bursts the pastille apart into fine sulphur particles, giving the bacteria the surface area they need. It's the standard way to bring neutral or alkaline ground down towards pH 5.0–6.0 for blueberries, rhododendrons, azaleas, camellias and blue hydrangeas.\u003c\/p\u003e\n\u003cp\u003eYou'll also see elemental sulphur sold as garden sulphur, yellow sulphur, sulphur chips or pastilles. Plain chips and granules have to weather down before much happens; the bentonite does that job for you in a few days. Because the acid is still made by soil biology it isn't instant — it works from spring to autumn when soils are warm, and rewards re-testing rather than guessing. Once you reach your target it holds the pH down for years.\u003c\/p\u003e\n\u003cdiv class=\"drf-stats\"\u003e\n\u003cdiv class=\"drf-stat\"\u003e\n\u003cspan class=\"drf-stat-number\"\u003e90%\u003c\/span\u003e\u003cspan class=\"drf-stat-label\"\u003eElemental sulphur (S)\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-stat\"\u003e\n\u003cspan class=\"drf-stat-number\"\u003epH 5–6\u003c\/span\u003e\u003cspan class=\"drf-stat-label\"\u003eEricaceous target\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-stat\"\u003e\n\u003cspan class=\"drf-stat-number\"\u003e150–300\u003c\/span\u003e\u003cspan class=\"drf-stat-label\"\u003eg\/m² per pH unit\u003c\/span\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-stat\"\u003e\n\u003cspan class=\"drf-stat-number\"\u003e2×\u003c\/span\u003e\u003cspan class=\"drf-stat-label\"\u003eH⁺ ions per S atom\u003c\/span\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch3\u003eWhat it's for\u003c\/h3\u003e\n\u003cul class=\"drf-uses\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eBlueberries \u0026amp; cranberries\u003c\/strong\u003e — the most acid-hungry, pH 4.5–5.5\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRhododendrons, azaleas \u0026amp; camellias\u003c\/strong\u003e — classic ericaceous shrubs, pH 4.5–6.0\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAcers, pieris \u0026amp; summer heathers\u003c\/strong\u003e — acid-loving structure and foliage. Winter heathers (\u003cem\u003eErica carnea\u003c\/em\u003e, \u003cem\u003eE.\u003c\/em\u003e × \u003cem\u003edarleyensis\u003c\/em\u003e) tolerate lime and do not need this\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBlue hydrangeas\u003c\/strong\u003e — keep the flowers blue (below about pH 5.5)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNeutral or alkaline beds\u003c\/strong\u003e — nudge them down for acid-lovers\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRaised beds \u0026amp; containers\u003c\/strong\u003e — mix in before planting\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSulphur vs the quick fixes\u003c\/h3\u003e\n\u003cdiv class=\"drf-compare\"\u003e\n\u003cdiv class=\"drf-compare-box\"\u003e\n\u003ch4\u003eSulphur-bentonite pastilles\u003c\/h4\u003e\n\u003cp\u003eGentlest on plants and the cheapest per pH unit. Handles like a granule, then breaks down to fine sulphur once wet, so it acts far quicker than plain chips. Still needs warm, moist soil and a few weeks to a few months, but the effect lasts 5+ years.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-compare-box\"\u003e\n\u003ch4\u003eIron or aluminium sulphate\u003c\/h4\u003e\n\u003cp\u003eAct faster, but you need roughly 7–8× as much for the same drop, they can lock up phosphorus, and aluminium can build up in the soil. Better for a quick nudge than a lasting change \u003cem\u003e(RHS)\u003c\/em\u003e.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-callout\"\u003e\n\u003cspan class=\"drf-callout-title\"\u003ePacked in Stockport\u003c\/span\u003e\n\u003cp\u003eWeighed and packed by hand in small batches at our workshop in Stockport, Greater Manchester. The pastilles themselves are made by co-melting sulphur with the bentonite — nothing we blend, and nothing we add to.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- ============ THE SCIENCE ============ --\u003e\n\u003cdiv id=\"drf-su-panel2\" class=\"drf-panel\"\u003e\n\u003ch2\u003eThe science: how sulphur acidifies soil\u003c\/h2\u003e\n\u003cp\u003eElemental sulphur doesn't acidify soil on its own. Sulphur-oxidising bacteria — mainly \u003cem\u003eThiobacillus\u003c\/em\u003e and \u003cem\u003eAcidithiobacillus\u003c\/em\u003e — use it as an energy source and convert it to sulphate, releasing hydrogen ions as they go. It's those H⁺ ions that lower pH.\u003c\/p\u003e\n\u003cdiv class=\"drf-callout drf-callout-gold\"\u003e\n\u003cspan class=\"drf-callout-title\"\u003eThe oxidation reaction\u003c\/span\u003e\n\u003cp\u003eCO₂ + S⁰ + ½O₂ + 2H₂O → CH₂O + SO₄²⁻ + \u003cstrong\u003e2H⁺\u003c\/strong\u003e — two hydrogen ions for every sulphur atom oxidised (Havlin et al., 1999; Ohio State Extension). The sulphate left behind is also a plant nutrient.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch3\u003eWarmth and moisture set the speed\u003c\/h3\u003e\n\u003cdiv class=\"drf-fig\"\u003e\n\u003csvg viewbox=\"0 0 680 320\" role=\"img\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\n\u003ctitle\u003eRelative sulphur oxidation rate versus soil temperature\u003c\/title\u003e\n\u003cdesc\u003eOxidation barely starts below about 5 degrees C, rises steeply and plateaus between 30 and 40 degrees C, then falls.\u003c\/desc\u003e\n\n\u003cline x1=\"70\" y1=\"30\" x2=\"70\" y2=\"250\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"70\" y1=\"250\" x2=\"655\" y2=\"250\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\n\u003cline x1=\"70\" y1=\"140\" x2=\"655\" y2=\"140\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"70\" y1=\"30\" x2=\"655\" y2=\"30\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003ctext x=\"62\" y=\"253\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e0\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"143\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e50\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"34\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e100\u003c\/text\u003e\n\u003ctext x=\"20\" y=\"145\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\" transform=\"rotate(-90 20 145)\"\u003eRelative oxidation (%)\u003c\/text\u003e\n\n\u003crect x=\"113.5\" y=\"30\" width=\"145\" height=\"220\" fill=\"#C5A55A\" opacity=\"0.12\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"186\" y=\"46\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#8b6914\"\u003eTypical UK soil 8–18°C\u003c\/text\u003e\n\n\u003cpolyline points=\"70,239 142.5,221 215,184 287.5,136 360,85 432.5,48 505,30 577.5,37 650,144\" fill=\"none\" stroke=\"#1B3D2F\" stroke-width=\"2.5\"\u003e\u003c\/polyline\u003e\n\n\u003cline x1=\"432.5\" y1=\"30\" x2=\"577.5\" y2=\"30\" stroke=\"#C5A55A\" stroke-width=\"3\"\u003e\u003c\/line\u003e\n\u003ctext x=\"505\" y=\"20\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"13\" fill=\"#1B3D2F\"\u003ePlateau ~30–40°C\u003c\/text\u003e\n\n\u003ctext x=\"70\" y=\"268\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e5\u003c\/text\u003e\n\u003ctext x=\"215\" y=\"268\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e15\u003c\/text\u003e\n\u003ctext x=\"360\" y=\"268\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e25\u003c\/text\u003e\n\u003ctext x=\"505\" y=\"268\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e35\u003c\/text\u003e\n\u003ctext x=\"650\" y=\"268\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e45\u003c\/text\u003e\n\u003ctext x=\"360\" y=\"290\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003eSoil temperature (°C)\u003c\/text\u003e\n\u003c\/svg\u003e\n\u003cdiv class=\"drf-fig-cap\"\u003e\n\u003cstrong\u003eTemperature drives the rate.\u003c\/strong\u003e Germida and Janzen's review names soil temperature, water potential and aeration as the primary constraints on elemental-sulphur oxidation. Of the three, temperature is the one you cannot manage: oxidation barely starts below about 5 °C and runs fastest between 30 and 40 °C. In practice that means spring-to-autumn application in UK gardens, where soils sit well below the optimum all year. \u003cem\u003eSources: Germida \u0026amp; Janzen, 1993; Yang et al., 2010.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch3\u003eWhy the bentonite is there\u003c\/h3\u003e\n\u003cdiv class=\"drf-fig\"\u003e\n\u003csvg viewbox=\"0 0 680 300\" role=\"img\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\n\u003ctitle\u003eRelative oxidation speed by sulphur form\u003c\/title\u003e\n\u003cdesc\u003eMilled powder oxidises fastest, a dispersed sulphur-bentonite pastille is close behind, a plain granule is slower and coarse chips slowest.\u003c\/desc\u003e\n\u003cline x1=\"70\" y1=\"40\" x2=\"70\" y2=\"230\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"70\" y1=\"230\" x2=\"645\" y2=\"230\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003crect x=\"110\" y=\"50\" width=\"100\" height=\"180\" fill=\"#4a7a5e\"\u003e\u003c\/rect\u003e\n\u003crect x=\"250\" y=\"82\" width=\"100\" height=\"148\" fill=\"#C5A55A\"\u003e\u003c\/rect\u003e\n\u003crect x=\"390\" y=\"149\" width=\"100\" height=\"81\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003crect x=\"530\" y=\"185\" width=\"100\" height=\"45\" fill=\"#0F2A1F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"160\" y=\"42\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"15\" fill=\"#1B3D2F\"\u003eFastest\u003c\/text\u003e\n\u003ctext x=\"300\" y=\"74\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"15\" fill=\"#8b6914\"\u003eClose behind\u003c\/text\u003e\n\u003ctext x=\"440\" y=\"141\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"15\" fill=\"#1B3D2F\"\u003eSlower\u003c\/text\u003e\n\u003ctext x=\"580\" y=\"177\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"15\" fill=\"#1B3D2F\"\u003eSlowest\u003c\/text\u003e\n\u003ctext x=\"160\" y=\"248\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003eMilled powder\u003c\/text\u003e\n\u003ctext x=\"160\" y=\"262\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10\" fill=\"#3A4A40\"\u003edusty, drifts\u003c\/text\u003e\n\u003ctext x=\"300\" y=\"248\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#8b6914\" font-weight=\"600\"\u003eBentonite pastille\u003c\/text\u003e\n\u003ctext x=\"300\" y=\"262\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10\" fill=\"#8b6914\" font-weight=\"600\"\u003eonce dispersed — Dr Forest\u003c\/text\u003e\n\u003ctext x=\"440\" y=\"248\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003ePlain granule\u003c\/text\u003e\n\u003ctext x=\"580\" y=\"248\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003eCoarse chips\u003c\/text\u003e\n\u003ctext x=\"30\" y=\"135\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\" transform=\"rotate(-90 30 135)\"\u003eOxidation speed\u003c\/text\u003e\n\u003c\/svg\u003e\n\u003cdiv class=\"drf-fig-cap\"\u003e\n\u003cstrong\u003eSurface area is everything, and the bentonite buys it.\u003c\/strong\u003e Sulphur is oxidised on the surface of each particle, so finer means faster. Milled powder is quickest but drifts and is unpleasant to handle. A sulphur-bentonite pastille gets most of the way there without the dust: the clay imbibes soil moisture and the pastille disintegrates into finely divided sulphur. The released particles are still a little coarser than milled powder, so it is not quite as quick — but it is well ahead of a plain granule or chip, which has to weather down on its own. \u003cem\u003eSources: The Sulphur Institute; Incitec Pivot Fertilisers Agritopic — Sulphur; Lee, Boswell \u0026amp; Watkinson, 1988.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch3\u003eHow far, how fast\u003c\/h3\u003e\n\u003cdiv class=\"drf-fig\"\u003e\n\u003csvg viewbox=\"0 0 680 330\" role=\"img\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\n\u003ctitle\u003eIllustrative soil pH response over time in warm versus cool soil\u003c\/title\u003e\n\u003cdesc\u003eAn illustration of pH falling from 7.0 towards the ericaceous target band, faster in warm soil than cool soil.\u003c\/desc\u003e\n\n\u003crect x=\"70\" y=\"160\" width=\"585\" height=\"120\" fill=\"#E8F0EB\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"648\" y=\"176\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#4a7a5e\"\u003eEricaceous target 5.0–6.0\u003c\/text\u003e\n\n\u003cline x1=\"70\" y1=\"40\" x2=\"70\" y2=\"280\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"70\" y1=\"280\" x2=\"655\" y2=\"280\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\n\u003ctext x=\"62\" y=\"44\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e7.0\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"104\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e6.5\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"164\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e6.0\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"224\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e5.5\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"284\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e5.0\u003c\/text\u003e\n\u003ctext x=\"24\" y=\"160\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\" transform=\"rotate(-90 24 160)\"\u003eSoil pH\u003c\/text\u003e\n\n\u003cpolyline points=\"70,40 166.7,100 263.3,148 360,184 456.7,202 650,214\" fill=\"none\" stroke=\"#C5A55A\" stroke-width=\"2.5\"\u003e\u003c\/polyline\u003e\n\n\u003cpolyline points=\"70,40 166.7,58 263.3,88 360,118 456.7,142 650,172\" fill=\"none\" stroke=\"#1B3D2F\" stroke-width=\"2\" stroke-dasharray=\"6 4\"\u003e\u003c\/polyline\u003e\n\n\u003ctext x=\"70\" y=\"298\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e0\u003c\/text\u003e\n\u003ctext x=\"263.3\" y=\"298\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e2\u003c\/text\u003e\n\u003ctext x=\"456.7\" y=\"298\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e4\u003c\/text\u003e\n\u003ctext x=\"650\" y=\"298\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e6\u003c\/text\u003e\n\u003ctext x=\"360\" y=\"318\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003eMonths after application\u003c\/text\u003e\n\n\u003cline x1=\"430\" y1=\"52\" x2=\"460\" y2=\"52\" stroke=\"#C5A55A\" stroke-width=\"2.5\"\u003e\u003c\/line\u003e\n\u003ctext x=\"465\" y=\"56\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003eWarm, moist soil\u003c\/text\u003e\n\u003cline x1=\"430\" y1=\"70\" x2=\"460\" y2=\"70\" stroke=\"#1B3D2F\" stroke-width=\"2\" stroke-dasharray=\"6 4\"\u003e\u003c\/line\u003e\n\u003ctext x=\"465\" y=\"74\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003eCool \/ heavy soil\u003c\/text\u003e\n\u003c\/svg\u003e\n\u003cdiv class=\"drf-fig-cap\"\u003e\n\u003cstrong\u003eIllustrative, not a guarantee.\u003c\/strong\u003e There is a short lag of several days while the sulphur-oxidising bacteria establish, then oxidation runs at a roughly constant rate per unit of exposed particle surface — so the pace eases later because the particles are shrinking, not because the bacteria tire. Warm, moist, well-worked soil moves within weeks; cool or heavy soil takes months. A large shift, such as neutral ground down to blueberry pH, takes one to two years whatever you do. Always re-test. \u003cem\u003ePattern after Watkinson \u0026amp; Blair, 1993; timescale after Longstroth, MSU Extension.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch3\u003eThe mechanism, in short\u003c\/h3\u003e\n\u003cdiv class=\"drf-mech\"\u003e\n\u003cspan class=\"drf-mech-num\"\u003e01\u003c\/span\u003e\n\u003ch4\u003eTwo protons per atom\u003c\/h4\u003e\n\u003cp\u003eThe acidity is biological: each sulphur atom oxidised releases 2 H⁺ (Havlin et al., 1999). No bacteria, no acid.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-mech\"\u003e\n\u003cspan class=\"drf-mech-num\"\u003e02\u003c\/span\u003e\n\u003ch4\u003eTemperature leads\u003c\/h4\u003e\n\u003cp\u003eTemperature, moisture and aeration are the three primary constraints on oxidation. Almost nothing happens below about 5 °C, and the rate peaks between 30 and 40 °C (Germida \u0026amp; Janzen, 1993; Yang et al., 2010).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-mech\"\u003e\n\u003cspan class=\"drf-mech-num\"\u003e03\u003c\/span\u003e\n\u003ch4\u003eBentonite makes the surface area\u003c\/h4\u003e\n\u003cp\u003eThe clay imbibes soil moisture and swells, bursting each pastille into finely divided sulphur that oxidises far faster than an intact granule (The Sulphur Institute). It has to wet where it lands to do that — see How to Use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-mech\"\u003e\n\u003cspan class=\"drf-mech-num\"\u003e04\u003c\/span\u003e\n\u003ch4\u003eBuffering sets the dose\u003c\/h4\u003e\n\u003cp\u003eClay and organic matter resist pH change, so they need far more sulphur than sand (RHS; Michigan State University Extension).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-mech\"\u003e\n\u003cspan class=\"drf-mech-num\"\u003e05\u003c\/span\u003e\n\u003ch4\u003eLong residual\u003c\/h4\u003e\n\u003cp\u003eOnce acidified, soil pH typically stays low for 5+ years — but keep testing (Ohio State Extension, AGF-507).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-mech\"\u003e\n\u003cspan class=\"drf-mech-num\"\u003e06\u003c\/span\u003e\n\u003ch4\u003eKeep it aerobic\u003c\/h4\u003e\n\u003cp\u003eIn waterlogged soil, sulphur turns to hydrogen sulphide instead of sulphate, which harms roots. Damp, not saturated (Michigan State University Extension).\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-refs\"\u003e\n\u003col\u003e\n\u003cli\u003eMullen R, Lentz E, Watson M (2016). \u003cem\u003eSoil Acidification: How to Lower Soil pH.\u003c\/em\u003e Ohio State University Extension, AGF-507.\u003c\/li\u003e\n\u003cli\u003eRoyal Horticultural Society. \u003cem\u003eAcidifying soil.\u003c\/em\u003e RHS Advice.\u003c\/li\u003e\n\u003cli\u003eGermida JJ, Janzen HH (1993). Factors affecting the oxidation of elemental sulfur in soils. \u003cem\u003eFertilizer Research\u003c\/em\u003e 35(1–2): 101–114. doi:10.1007\/BF00750224. (This journal is now published as \u003cem\u003eNutrient Cycling in Agroecosystems\u003c\/em\u003e.)\u003c\/li\u003e\n\u003cli\u003eWatkinson JH, Blair GJ (1993). Modelling the oxidation of elemental sulfur in soils. \u003cem\u003eFertilizer Research\u003c\/em\u003e 35: 115–126. doi:10.1007\/BF00750225\u003c\/li\u003e\n\u003cli\u003eLee A, Boswell CC, Watkinson JH (1988). Effect of particle size on the oxidation of elemental sulphur, thiobacilli numbers, soil sulphate, and its availability to pasture. \u003cem\u003eNew Zealand Journal of Agricultural Research\u003c\/em\u003e 31(2): 179–186. doi:10.1080\/00288233.1988.10417943\u003c\/li\u003e\n\u003cli\u003eYang Z-H, Stöven K, Haneklaus S, Singh BR, Schnug E (2010). Elemental sulfur oxidation by \u003cem\u003eThiobacillus\u003c\/em\u003e spp. and aerobic heterotrophic sulfur-oxidizing bacteria. \u003cem\u003ePedosphere\u003c\/em\u003e 20(1): 71–79.\u003c\/li\u003e\n\u003cli\u003eHavlin JL, Beaton JD, Tisdale SL, Nelson WL (1999). \u003cem\u003eSoil Fertility and Fertilizers: An Introduction to Nutrient Management,\u003c\/em\u003e 6th ed. Upper Saddle River, NJ: Prentice Hall.\u003c\/li\u003e\n\u003cli\u003eLongstroth M (n.d.). \u003cem\u003eLowering the Soil pH with Sulfur.\u003c\/em\u003e Michigan State University Extension.\u003c\/li\u003e\n\u003cli\u003eThe Sulphur Institute. \u003cem\u003eElemental Sulphur\u003c\/em\u003e (sulphur fertilizer types).\u003c\/li\u003e\n\u003cli\u003eIncitec Pivot Fertilisers. \u003cem\u003eAgritopic: Sulphur.\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eUniversity of Georgia CAES. \u003cem\u003eBackyard blueberry leaves can tell the tale of soil deficiencies and pH problems.\u003c\/em\u003e\n\u003c\/li\u003e\n\u003cli\u003eCornell University. \u003cem\u003eBerry Diagnostic Tool — blueberries: iron deficiency.\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- ============ HOW TO USE ============ --\u003e\n\u003cdiv id=\"drf-su-panel3\" class=\"drf-panel\"\u003e\n\u003ch2\u003eHow to use sulphur to lower soil pH\u003c\/h2\u003e\n\u003cdiv class=\"drf-callout drf-callout-gold\"\u003e\n\u003cspan class=\"drf-callout-title\"\u003eTest first, then go gently\u003c\/span\u003e\n\u003cp\u003eOnly acidify if your soil is neutral or alkaline — check with a pH kit. Drop a little vinegar on the soil first: if it fizzes, there's free lime or chalk and it can't realistically be acidified (RHS). Wear gloves, work in still air, and err on the side of too little — you can always add more.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch3\u003eHow much to use\u003c\/h3\u003e\n\u003cdiv class=\"drf-fig\"\u003e\n\u003csvg viewbox=\"0 0 680 300\" role=\"img\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\n\u003ctitle\u003eSulphur needed by soil type to lower pH by about one unit\u003c\/title\u003e\n\u003cdesc\u003eAbout 150 grams of product per square metre on sand, 220 on loam, and 300 on clay.\u003c\/desc\u003e\n\u003cline x1=\"70\" y1=\"40\" x2=\"70\" y2=\"230\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"70\" y1=\"230\" x2=\"640\" y2=\"230\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\n\u003cline x1=\"70\" y1=\"170\" x2=\"640\" y2=\"170\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"70\" y1=\"110\" x2=\"640\" y2=\"110\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"70\" y1=\"50\" x2=\"640\" y2=\"50\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003ctext x=\"62\" y=\"233\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e0\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"173\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e100\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"113\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e200\u003c\/text\u003e\n\u003ctext x=\"62\" y=\"53\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003e300\u003c\/text\u003e\n\u003ctext x=\"26\" y=\"135\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\" transform=\"rotate(-90 26 135)\"\u003eg per m²\u003c\/text\u003e\n\n\u003crect x=\"120\" y=\"140\" width=\"100\" height=\"90\" fill=\"#4a7a5e\"\u003e\u003c\/rect\u003e\n\u003crect x=\"295\" y=\"98\" width=\"100\" height=\"132\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003crect x=\"470\" y=\"50\" width=\"100\" height=\"180\" fill=\"#0F2A1F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"170\" y=\"132\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"16\" fill=\"#1B3D2F\"\u003e150\u003c\/text\u003e\n\u003ctext x=\"345\" y=\"90\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"16\" fill=\"#1B3D2F\"\u003e220\u003c\/text\u003e\n\u003ctext x=\"520\" y=\"42\" text-anchor=\"middle\" font-family=\"Cormorant Garamond,serif\" font-size=\"16\" fill=\"#1B3D2F\"\u003e300\u003c\/text\u003e\n\u003ctext x=\"170\" y=\"248\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003eSandy\u003c\/text\u003e\n\u003ctext x=\"345\" y=\"248\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003eLoam\u003c\/text\u003e\n\u003ctext x=\"520\" y=\"248\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003eClay \/ organic\u003c\/text\u003e\n\u003c\/svg\u003e\n\u003cdiv class=\"drf-fig-cap\"\u003e\n\u003cstrong\u003eRule of thumb for the top 15 cm.\u003c\/strong\u003e About 150 g of product per m² on sandy soil, up to 300 g\/m² on clay, with loam between at around 220 g\/m². RHS puts that dose as enough to move the top 15 cm from pH 7.0–7.5 down to pH 6.0–6.5 — so depending where you start and what your soil is like, expect anywhere from half a point to one and a half. For a smaller shift, halve it. \u003cem\u003eSource: RHS elemental-sulphur figures (135–270 g\/m², top 15 cm), divided by 0.9 for the 90% pastille. RHS specifies sulphur powder; the loam value is our interpolation, as RHS publishes none.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eSoil type\u003c\/th\u003e\n\u003cth\u003eDrop ~0.5 pH\u003c\/th\u003e\n\u003cth\u003eDrop ~1.0 pH\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSandy\u003c\/td\u003e\n\u003ctd\u003e~75 g\/m²\u003c\/td\u003e\n\u003ctd\u003e~150 g\/m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLoam\u003c\/td\u003e\n\u003ctd\u003e~110 g\/m²\u003c\/td\u003e\n\u003ctd\u003e~220 g\/m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eClay \/ high organic\u003c\/td\u003e\n\u003ctd\u003e~150 g\/m²\u003c\/td\u003e\n\u003ctd\u003e~300 g\/m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eThese are weights of \u003cstrong\u003eproduct\u003c\/strong\u003e, which is what you actually scoop. Because the pastilles are 90% sulphur they deliver the RHS elemental-sulphur figures for the top 15 cm — 70, 100 and 135 g\/m² for the smaller shift, 135, 200 and 270 g\/m² for the larger. One honest caveat: RHS quotes those rates for sulphur powder. The bentonite is there to break these pastilles down to fine sulphur in the soil, which gets you close, though the particles it releases stay a little coarser than a mill would give. Test and repeat rather than over-dose — over-acidified soil has to be limed back.\u003c\/em\u003e\u003c\/p\u003e\n\u003ch3\u003eWhat you're aiming for\u003c\/h3\u003e\n\u003cdiv class=\"drf-fig\"\u003e\n\u003csvg viewbox=\"0 0 680 340\" role=\"img\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\n\u003ctitle\u003eTarget soil pH ranges by plant\u003c\/title\u003e\n\u003cdesc\u003eBlueberries and blue hydrangeas 4.5 to 5.5; rhododendron, azalea, pieris and summer heather 4.5 to 6.0; camellia 5.0 to 6.5; veg, top fruit and lawns 6.0 to 7.0.\u003c\/desc\u003e\n\n\u003crect x=\"312.1\" y=\"45\" width=\"137.2\" height=\"248\" fill=\"#C5A55A\" opacity=\"0.12\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"380\" y=\"40\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#8b6914\"\u003eEricaceous zone 5.0–6.0\u003c\/text\u003e\n\n\u003cline x1=\"586.4\" y1=\"45\" x2=\"586.4\" y2=\"293\" stroke=\"#4a7a5e\" stroke-width=\"1\" stroke-dasharray=\"4 4\"\u003e\u003c\/line\u003e\n\u003ctext x=\"586.4\" y=\"308\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#4a7a5e\"\u003eNeutral 7.0\u003c\/text\u003e\n\n\u003ctext x=\"12\" y=\"72\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#1B3D2F\"\u003eBlueberry\u003c\/text\u003e\n\u003crect x=\"243.6\" y=\"61\" width=\"137.1\" height=\"20\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"12\" y=\"117\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#1B3D2F\"\u003eBlue hydrangea\u003c\/text\u003e\n\u003crect x=\"243.6\" y=\"106\" width=\"137.1\" height=\"20\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"12\" y=\"162\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#1B3D2F\"\u003eRhododendron \/ azalea\u003c\/text\u003e\n\u003crect x=\"243.6\" y=\"151\" width=\"205.7\" height=\"20\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"12\" y=\"207\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#1B3D2F\"\u003ePieris \u0026amp; summer heather\u003c\/text\u003e\n\u003crect x=\"243.6\" y=\"196\" width=\"205.7\" height=\"20\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"12\" y=\"252\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#1B3D2F\"\u003eCamellia\u003c\/text\u003e\n\u003crect x=\"312.1\" y=\"241\" width=\"205.7\" height=\"20\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"12\" y=\"285\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003eVeg, top fruit \u0026amp; lawns\u003c\/text\u003e\n\u003crect x=\"449.3\" y=\"274\" width=\"137.1\" height=\"16\" fill=\"#4a7a5e\"\u003e\u003c\/rect\u003e\n\n\u003cline x1=\"175\" y1=\"298\" x2=\"655\" y2=\"298\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003ctext x=\"175\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e4.0\u003c\/text\u003e\n\u003ctext x=\"243.6\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e4.5\u003c\/text\u003e\n\u003ctext x=\"312.1\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e5.0\u003c\/text\u003e\n\u003ctext x=\"380.7\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e5.5\u003c\/text\u003e\n\u003ctext x=\"449.3\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e6.0\u003c\/text\u003e\n\u003ctext x=\"517.9\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e6.5\u003c\/text\u003e\n\u003ctext x=\"586.4\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e7.0\u003c\/text\u003e\n\u003ctext x=\"655\" y=\"316\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e7.5\u003c\/text\u003e\n\u003ctext x=\"415\" y=\"334\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003eSoil pH\u003c\/text\u003e\n\u003c\/svg\u003e\n\u003cdiv class=\"drf-fig-cap\"\u003e\n\u003cstrong\u003eWhere to aim.\u003c\/strong\u003e Most ericaceous plants are happy at pH 5.0–6.0; blueberries and blue hydrangeas want it lower, around 4.5–5.5. Blueberries are the least forgiving: above about pH 5.3 they begin to show iron chlorosis, the youngest leaves going yellow while the veins stay dark green. That is more than a point below neutral, which is why blueberry ground almost always needs correcting. Blue hydrangeas need available aluminium in the soil as well as a low pH — pH alone will not turn them blue. \u003cem\u003eSources: RHS; University of Georgia Extension; Cornell Berry Diagnostic Tool.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch3\u003eApplication rates\u003c\/h3\u003e\n\u003cdiv class=\"drf-rate\"\u003e\n\u003ch4\u003eOpen ground \u0026amp; beds\u003c\/h4\u003e\n\u003cdiv class=\"drf-rate-meta\"\u003e\n\u003cstrong\u003eRate:\u003c\/strong\u003e 150–300 g\/m² per pH unit (top 15 cm)  |  \u003cstrong\u003eWhen:\u003c\/strong\u003e spring–autumn, ideally before planting\u003c\/div\u003e\n\u003cp\u003eBroadcast evenly on the surface and water it. Leave it a few days for the pastilles to swell and break down, \u003cem\u003ethen\u003c\/em\u003e fork into the top 15 cm. Burying them intact concentrates the sulphur into a small volume and slows everything down. Sandy soils take the lower rate, clay the higher. Re-test after 8–12 weeks and top up if needed.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-rate\"\u003e\n\u003ch4\u003eContainers \u0026amp; raised beds\u003c\/h4\u003e\n\u003cdiv class=\"drf-rate-meta\"\u003e\n\u003cstrong\u003eRate:\u003c\/strong\u003e acidify the mix before planting  |  \u003cstrong\u003eWhen:\u003c\/strong\u003e at potting\u003c\/div\u003e\n\u003cp\u003eFor pots, it's safer to acidify peat-free ericaceous compost before planting than to dose a planted pot. Reckon on about 1.0 g per litre of mix on sandy blends, 1.5 g\/L on loam and 2.0 g\/L on compost-rich ones, for one pH point. Wet the mix so the pastilles break down, turn it through, then leave it a few weeks before testing. Avoid heavy doses around established roots.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-rate\"\u003e\n\u003ch4\u003eEstablished ericaceous plants\u003c\/h4\u003e\n\u003cdiv class=\"drf-rate-meta\"\u003e\n\u003cstrong\u003eRate:\u003c\/strong\u003e light spring dressing  |  \u003cstrong\u003eWhen:\u003c\/strong\u003e growing season\u003c\/div\u003e\n\u003cp\u003eFor blueberries, rhododendrons and camellias already in the ground, scatter a light surface dressing in spring and water it in — no digging needed, since the pastilles break down where they land and the acid moves down with the rain. Re-test before repeating. Small and often beats one big dose.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003chr class=\"drf-sep\"\u003e\n\u003ch3\u003eWhich bag size do you need?\u003c\/h3\u003e\n\u003cp\u003eSulphur is dosed by area, so the sum is simple: \u003cstrong\u003eyour area in m² × the rate for your soil = grams of product needed\u003c\/strong\u003e. A 6 m² border on loam wanting a full pH point needs 6 × 220 = 1,320 g, so the 1.5kg bag. The chart and tables below do that arithmetic for every bag size.\u003c\/p\u003e\n\u003cdiv class=\"drf-fig\"\u003e\n\u003csvg viewbox=\"0 0 680 300\" role=\"img\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"\u003e\n\u003ctitle\u003eArea treated by each bag size on loam soil\u003c\/title\u003e\n\u003cdesc\u003eOn loam at 220 grams of product per square metre, 500g treats 2.3 square metres, 1.5kg treats 6.8, 4kg treats 18, 9kg treats 41, 18kg treats 82 and 36kg treats 164.\u003c\/desc\u003e\n\u003cline x1=\"110\" y1=\"35\" x2=\"110\" y2=\"268\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"110\" y1=\"268\" x2=\"620\" y2=\"268\" stroke=\"#d4cfc5\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"259\" y1=\"35\" x2=\"259\" y2=\"268\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"409\" y1=\"35\" x2=\"409\" y2=\"268\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003cline x1=\"558\" y1=\"35\" x2=\"558\" y2=\"268\" stroke=\"#efece4\" stroke-width=\"1\"\u003e\u003c\/line\u003e\n\u003crect x=\"110\" y=\"45\" width=\"7\" height=\"26\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003crect x=\"110\" y=\"83\" width=\"20\" height=\"26\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003crect x=\"110\" y=\"121\" width=\"54\" height=\"26\" fill=\"#C5A55A\"\u003e\u003c\/rect\u003e\n\u003crect x=\"110\" y=\"159\" width=\"123\" height=\"26\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003crect x=\"110\" y=\"197\" width=\"245\" height=\"26\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003crect x=\"110\" y=\"235\" width=\"490\" height=\"26\" fill=\"#1B3D2F\"\u003e\u003c\/rect\u003e\n\u003ctext x=\"100\" y=\"63\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003e500g\u003c\/text\u003e\n\u003ctext x=\"100\" y=\"101\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003e1.5kg\u003c\/text\u003e\n\u003ctext x=\"100\" y=\"139\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#8b6914\" font-weight=\"600\"\u003e4kg\u003c\/text\u003e\n\u003ctext x=\"100\" y=\"177\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003e9kg\u003c\/text\u003e\n\u003ctext x=\"100\" y=\"215\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003e18kg\u003c\/text\u003e\n\u003ctext x=\"100\" y=\"253\" text-anchor=\"end\" font-family=\"Jost,sans-serif\" font-size=\"11.5\" fill=\"#3A4A40\"\u003e36kg\u003c\/text\u003e\n\u003ctext x=\"125\" y=\"63\" font-family=\"Cormorant Garamond,serif\" font-size=\"14\" fill=\"#1B3D2F\"\u003e2.3 m²\u003c\/text\u003e\n\u003ctext x=\"138\" y=\"101\" font-family=\"Cormorant Garamond,serif\" font-size=\"14\" fill=\"#1B3D2F\"\u003e6.8 m²\u003c\/text\u003e\n\u003ctext x=\"172\" y=\"139\" font-family=\"Cormorant Garamond,serif\" font-size=\"14\" fill=\"#8b6914\"\u003e18 m²\u003c\/text\u003e\n\u003ctext x=\"241\" y=\"177\" font-family=\"Cormorant Garamond,serif\" font-size=\"14\" fill=\"#1B3D2F\"\u003e41 m²\u003c\/text\u003e\n\u003ctext x=\"363\" y=\"215\" font-family=\"Cormorant Garamond,serif\" font-size=\"14\" fill=\"#1B3D2F\"\u003e82 m²\u003c\/text\u003e\n\u003ctext x=\"592\" y=\"253\" text-anchor=\"end\" font-family=\"Cormorant Garamond,serif\" font-size=\"14\" fill=\"#F5F2EC\"\u003e164 m²\u003c\/text\u003e\n\u003ctext x=\"110\" y=\"286\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e0\u003c\/text\u003e\n\u003ctext x=\"259\" y=\"286\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e50\u003c\/text\u003e\n\u003ctext x=\"409\" y=\"286\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e100\u003c\/text\u003e\n\u003ctext x=\"558\" y=\"286\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"10.5\" fill=\"#3A4A40\"\u003e150\u003c\/text\u003e\n\u003ctext x=\"365\" y=\"26\" text-anchor=\"middle\" font-family=\"Jost,sans-serif\" font-size=\"11\" fill=\"#3A4A40\"\u003eArea treated (m²) — loam, one full pH unit\u003c\/text\u003e\n\u003c\/svg\u003e\n\u003cdiv class=\"drf-fig-cap\"\u003e\n\u003cstrong\u003eLoam at 220 g of product per m², one full pH point.\u003c\/strong\u003e Sandy soil goes roughly a third further; clay covers about a third less. The 4kg bag is the usual choice for a garden border. \u003cem\u003eDerived from the rates above.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch4\u003eArea each bag treats\u003c\/h4\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eBag\u003c\/th\u003e\n\u003cth\u003eSandy\u003c\/th\u003e\n\u003cth\u003eLoam\u003c\/th\u003e\n\u003cth\u003eClay \/ high organic\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e500g\u003c\/td\u003e\n\u003ctd\u003e3.3 m²\u003c\/td\u003e\n\u003ctd\u003e2.3 m²\u003c\/td\u003e\n\u003ctd\u003e1.7 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1.5kg\u003c\/td\u003e\n\u003ctd\u003e10 m²\u003c\/td\u003e\n\u003ctd\u003e6.8 m²\u003c\/td\u003e\n\u003ctd\u003e5.0 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e4kg\u003c\/td\u003e\n\u003ctd\u003e27 m²\u003c\/td\u003e\n\u003ctd\u003e18 m²\u003c\/td\u003e\n\u003ctd\u003e13 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e9kg\u003c\/td\u003e\n\u003ctd\u003e60 m²\u003c\/td\u003e\n\u003ctd\u003e41 m²\u003c\/td\u003e\n\u003ctd\u003e30 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e18kg\u003c\/td\u003e\n\u003ctd\u003e120 m²\u003c\/td\u003e\n\u003ctd\u003e82 m²\u003c\/td\u003e\n\u003ctd\u003e60 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e36kg\u003c\/td\u003e\n\u003ctd\u003e240 m²\u003c\/td\u003e\n\u003ctd\u003e164 m²\u003c\/td\u003e\n\u003ctd\u003e120 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eOne full pH unit in the top 15 cm. For a half-point drop, every figure doubles — a 4kg bag covers 36 m² of loam instead of 18.\u003c\/em\u003e\u003c\/p\u003e\n\u003ch4\u003eBuying for a full year\u003c\/h4\u003e\n\u003cp\u003eMost people need more than the initial dose. Even with the bentonite doing the grinding for you, oxidation is biological and the first season is variable, so the honest planning assumption is one full application in spring, a re-test at 8–12 weeks, and a half-rate top-up in late summer if you are not there yet. That is \u003cstrong\u003e1.5× the initial figure\u003c\/strong\u003e across the first year.\u003c\/p\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eBag\u003c\/th\u003e\n\u003cth\u003eSandy\u003c\/th\u003e\n\u003cth\u003eLoam\u003c\/th\u003e\n\u003cth\u003eClay \/ high organic\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e500g\u003c\/td\u003e\n\u003ctd\u003e2.2 m²\u003c\/td\u003e\n\u003ctd\u003e1.5 m²\u003c\/td\u003e\n\u003ctd\u003e1.1 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1.5kg\u003c\/td\u003e\n\u003ctd\u003e6.7 m²\u003c\/td\u003e\n\u003ctd\u003e4.5 m²\u003c\/td\u003e\n\u003ctd\u003e3.3 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e4kg\u003c\/td\u003e\n\u003ctd\u003e18 m²\u003c\/td\u003e\n\u003ctd\u003e12 m²\u003c\/td\u003e\n\u003ctd\u003e8.9 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e9kg\u003c\/td\u003e\n\u003ctd\u003e40 m²\u003c\/td\u003e\n\u003ctd\u003e27 m²\u003c\/td\u003e\n\u003ctd\u003e20 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e18kg\u003c\/td\u003e\n\u003ctd\u003e80 m²\u003c\/td\u003e\n\u003ctd\u003e55 m²\u003c\/td\u003e\n\u003ctd\u003e40 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e36kg\u003c\/td\u003e\n\u003ctd\u003e160 m²\u003c\/td\u003e\n\u003ctd\u003e109 m²\u003c\/td\u003e\n\u003ctd\u003e80 m²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eYear one, including the likely top-up. After that the pH holds for years and you are only maintaining, so a bag lasts far longer.\u003c\/em\u003e\u003c\/p\u003e\n\u003ch4\u003eTypical projects\u003c\/h4\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eWhat you are doing\u003c\/th\u003e\n\u003cth\u003eYear one, loam\u003c\/th\u003e\n\u003cth\u003eBag\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOne blueberry in a 45 cm pot (~40 L)\u003c\/td\u003e\n\u003ctd\u003e~80 g\u003c\/td\u003e\n\u003ctd\u003e500g does 6 pots\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThree blueberries, 2 m × 1 m bed\u003c\/td\u003e\n\u003ctd\u003e660 g\u003c\/td\u003e\n\u003ctd\u003e1.5kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRhododendron border, 5 m × 1.5 m\u003c\/td\u003e\n\u003ctd\u003e2,475 g\u003c\/td\u003e\n\u003ctd\u003e4kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNew ericaceous bed, 10 m²\u003c\/td\u003e\n\u003ctd\u003e3,300 g\u003c\/td\u003e\n\u003ctd\u003e4kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAcid border or small blueberry patch, 25 m²\u003c\/td\u003e\n\u003ctd\u003e8,250 g\u003c\/td\u003e\n\u003ctd\u003e9kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLarge planting, 100 m²\u003c\/td\u003e\n\u003ctd\u003e33,000 g\u003c\/td\u003e\n\u003ctd\u003e36kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eOn clay, add about a third. On sand, take about a quarter off.\u003c\/em\u003e\u003c\/p\u003e\n\u003cdiv class=\"drf-callout drf-callout-gold\"\u003e\n\u003cspan class=\"drf-callout-title\"\u003ePots and raised beds — working by volume\u003c\/span\u003e\n\u003cp\u003eThe rates above cover the top 15 cm, which is 150 litres of soil per square metre. Divide through and you get roughly \u003cstrong\u003e1.0 g per litre on sandy mixes, 1.5 g\/L on loam and 2.0 g\/L on compost-rich or clay mixes\u003c\/strong\u003e, for one pH point. A 40 L pot is therefore about 60–80 g. Wet the mix so the pastilles break down, turn it through before planting, and leave it a few weeks before testing — dosing a pot that already has a plant in it is much easier to overdo.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003ch3\u003eStep by step\u003c\/h3\u003e\n\u003col class=\"drf-steps\"\u003e\n\u003cli\u003e\n\u003cstrong\u003eTest your soil.\u003c\/strong\u003e Take a pH reading and do the vinegar-fizz check for free lime.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWork out the rate.\u003c\/strong\u003e Use your soil type and how far you need to drop (table above).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeigh it out.\u003c\/strong\u003e A level tablespoon of granules is roughly 15–18 g — measure rather than guess.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBroadcast on the surface.\u003c\/strong\u003e Scatter evenly across the area. Do not bury the pastilles yet.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWater, and give it a few days.\u003c\/strong\u003e The bentonite swells and breaks each pastille into fine sulphur — you will see them slump and spread.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNow fork it in.\u003c\/strong\u003e Work the dispersed sulphur into the top 15 cm and keep the soil damp. The bacteria need moisture and air, never waterlogged.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRe-test after 8–12 weeks.\u003c\/strong\u003e Top up cautiously if you're not there yet; it's easy to overshoot.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cdiv class=\"drf-callout\"\u003e\n\u003cspan class=\"drf-callout-title\"\u003eWorks well alongside\u003c\/span\u003e\n\u003cp\u003eOnce the pH is right, feed acid-lovers gently. Our \u003ca href=\"https:\/\/www.drforest.co.uk\/products\/dr-forests-organic-sulphate-potash-fertiliser-50\"\u003eSulphate of Potash\u003c\/a\u003e gives fruiting blueberries chloride-free potash, and \u003ca href=\"https:\/\/www.drforest.co.uk\/products\/organic-scottish-seaweed-kelp-meal-fertiliser\"\u003eSeaweed Plant Food\u003c\/a\u003e is a mild, pH-safe biostimulant. If you want sulphur and calcium \u003cem\u003ewithout\u003c\/em\u003e lowering pH, that's a job for gypsum — not this.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c!-- ============ FAQ ============ --\u003e\n\u003cdiv id=\"drf-su-panel4\" class=\"drf-panel\"\u003e\n\u003ch2\u003eSulphur soil acidifier — questions\u003c\/h2\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq1\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq1\" class=\"drf-faq-q\"\u003eWhat does sulphur do to soil?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eSoil bacteria oxidise elemental sulphur into sulphuric acid, which lowers pH. That frees up iron and manganese for acid-loving plants and leaves behind sulphate, a plant nutrient. It only acidifies — it won't raise pH.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq2\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq2\" class=\"drf-faq-q\"\u003eHow long does it take to lower soil pH?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eIt depends how far you are going. A modest correction — say half a point to a point on ordinary garden soil — takes weeks in warm, moist ground and months if it is cold or heavy; RHS puts it at weeks, or months over winter. A large shift is a different proposition: Michigan State reckon on one to two years to bring neutral soil down to blueberry pH, and up to five years of annual applications if the plants are already in the ground. Apply spring to autumn, re-test after 8–12 weeks, and judge it on the meter rather than the calendar.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq3\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq3\" class=\"drf-faq-q\"\u003eHow much sulphur do I need?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eRoughly 150 g of product per m² on sand, up to 300 g\/m² on clay, to drop about one pH point in the top 15 cm; halve that for a half-point. Those are product weights — at 90% sulphur they deliver the RHS elemental-sulphur rates of 135–270 g\/m². Always test first, because clay and organic-rich soils buffer the change and need more.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq4\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq4\" class=\"drf-faq-q\"\u003eWill it make soil acidic enough for blueberries?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eYes, but give it time. Blueberries want pH 4.5–5.5, and on neutral or clay soil that is a big shift — Michigan State put it at one to two years, not one season, and advise applying and incorporating at least a year before planting. For bushes already in the ground, they cap the rate and spread it across several years rather than dosing heavily in one go. Correct the ground first, test, then plant.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq5\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq5\" class=\"drf-faq-q\"\u003eCan I use it on established plants and in pots?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eYes, carefully. For pots, acidify the compost before planting. For plants already in the ground, use light spring dressings watered in, rather than one heavy dose around the roots.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq6\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq6\" class=\"drf-faq-q\"\u003eSulphur, or iron \/ aluminium sulphate?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eSulphur is the gentlest and cheapest per pH unit and lasts for years, but it's slow. Iron and aluminium sulphates act faster, yet you need about 7–8× as much and they can tie up phosphorus, with aluminium building up over time (RHS).\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq7\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq7\" class=\"drf-faq-q\"\u003eIs it safe for children, pets, bees and wildlife?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eIt's a natural mineral used widely in gardens, and the granules are low-dust. As with any soil product, wear gloves, keep it out of eyes, store it sealed and don't over-apply.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq8\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq8\" class=\"drf-faq-q\"\u003eIs it organic?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eTwo naturally occurring minerals and nothing else: elemental sulphur with 10% bentonite, a natural swelling clay that is there to break the pastille down in the soil. Both are used by organic gardeners. We don't make certified-organic claims.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq9\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq9\" class=\"drf-faq-q\"\u003eWhy isn't my soil pH changing?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eUsually one of three things: the soil is too cold, it's waterlogged (which turns sulphur to hydrogen sulphide instead of acid), or there's free lime or chalk buffering it. Do the vinegar-fizz test — if it fizzes, sulphur won't hold (RHS; Michigan State University Extension).\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq10\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq10\" class=\"drf-faq-q\"\u003eWhere is it made?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eWeighed and packed by hand in small batches by Dr Forest in Stockport, Greater Manchester. The sulphur-bentonite pastilles are manufactured by co-melting the two minerals together, so what reaches you is exactly that and nothing else.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq12\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq12\" class=\"drf-faq-q\"\u003eWhy is there bentonite clay in it?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eTo break the pastille apart. Sulphur is oxidised on the surface of each particle, so fine sulphur works and lumps don't — but fine sulphur is dusty, drifts on the wind and is unpleasant to spread. Ten per cent bentonite solves both problems at once: the pastille handles like a granule, then the clay imbibes soil moisture, swells and bursts it into finely divided sulphur exactly where you put it. The bentonite itself does no harm — it is an inert clay mineral, and if anything it slightly improves the soil's ability to hold nutrients.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"drf-faq\"\u003e\n\u003cinput id=\"drf-su-faq11\" type=\"checkbox\"\u003e\u003clabel for=\"drf-su-faq11\" class=\"drf-faq-q\"\u003eIs this the same as sulphur chips or garden sulphur?\u003c\/label\u003e\n\u003cdiv class=\"drf-faq-a\"\u003e\n\u003cdiv\u003eSame mineral, different form. \"Garden sulphur\", \"yellow sulphur\" and \"sulphur chips\" usually mean plain elemental sulphur, which has to weather down before it does much. Ours is a sulphur-bentonite pastille — 90% sulphur, 10% clay — spread dust-free, then breaking itself into fine sulphur the moment it gets wet. Powder-like speed with granule-like handling.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Dr Forest","offers":[{"title":"500g","offer_id":58253637058934,"sku":"DF-SULPHUR-500G","price":7.0,"currency_code":"GBP","in_stock":true},{"title":"1.5kg","offer_id":58378201661814,"sku":"DF-SULPHUR-1.5","price":12.0,"currency_code":"GBP","in_stock":true},{"title":"4kg","offer_id":58378201694582,"sku":"DF-SULPHUR-4","price":24.25,"currency_code":"GBP","in_stock":true},{"title":"9kg","offer_id":58378201727350,"sku":"DF-SULPHUR-9","price":44.0,"currency_code":"GBP","in_stock":true},{"title":"18kg","offer_id":58378201760118,"sku":"DF-SULPHUR-18","price":66.0,"currency_code":"GBP","in_stock":true},{"title":"36kg","offer_id":58378201792886,"sku":"DF-SULPHUR-36","price":129.25,"currency_code":"GBP","in_stock":true}],"url":"https:\/\/www.drforest.co.uk\/products\/sulphur-soil-acidifier","provider":"Dr Forest","version":"1.0","type":"link"}