{"product_id":"shogun-calmag","title":"Shogun CalMag – Calcium \u0026 Magnesium Supplement for Coco, Soft Water \u0026 Houseplants","description":"\u003cp\u003e\u003cstrong\u003e⚙️ Type: Mineral\u003c\/strong\u003e\u003cbr\u003eRefined minerals your plant can use straight away: fast-acting and precise. The tradeoff: it's possible to overdo mineral feeds, so stick to the dose and check your EC.\u003c\/p\u003e\n\u003ch3\u003eThe supplement nobody budgets for, and everybody ends up needing\u003c\/h3\u003e\n\u003cp\u003eThere is a curious hierarchy in plant feeding. Nitrogen gets top billing. Phosphorus and potassium get flashy \"bloom booster\" bottles with pictures of enormous tomatoes on them. Calcium and magnesium get nothing at all, which is odd, because they're the two elements most likely to run out first.\u003c\/p\u003e\n\u003cp\u003eAnd when they run out, nothing dramatic happens. There's no collapse, no crisis. Just rusty brown spots, yellowing between the leaf veins, weak new growth and a plant that is somehow underperforming without anyone being able to say why. It's the horticultural equivalent of a slow puncture.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSHOGUN CalMag is the fix that costs pennies a watering.\u003c\/strong\u003e It's a refined, plant-available blend of calcium, magnesium, nitrogen and chelated iron, designed by Shogun to do more than plug a gap. Calcium and magnesium are the delivery drivers of the plant world, helping move other nutrients to where they're needed. Keep them topped up and everything else in your feed works harder.\u003c\/p\u003e\n\u003ch3\u003eWho needs CalMag? More people than think they do\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eCoco coir growers:\u003c\/b\u003e Coco naturally holds on to calcium and magnesium, stealing them from your feed. CalMag is close to essential in coco, especially through vegetative growth.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSoft water areas:\u003c\/b\u003e Much of Scotland, Wales, the North and the South West has soft tap water with very little calcium or magnesium in it.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eRO, filtered and rainwater users:\u003c\/b\u003e The purer the water, the emptier it is. Great for fussy plants, but it leaves them short of minerals.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eLED growers:\u003c\/b\u003e Plants under LEDs transpire less, so they draw up less calcium. A little CalMag closes the gap.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eHouseplant collectors:\u003c\/b\u003e Watering Calathea, Maranta, ferns or Alocasia with rainwater or a filter jug? Add a splash of CalMag and they get the minerals their water no longer provides.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eHeatwaves and growth spurts:\u003c\/b\u003e Fast-growing plants in hot weather burn through calcium quickly, which is when deficiencies usually appear.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpot the signs\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eMagnesium deficiency:\u003c\/b\u003e Yellowing between the veins of older, lower leaves while the veins stay green.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eCalcium deficiency:\u003c\/b\u003e Rusty brown spots, crinkled or twisted new leaves and weak stems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eIron deficiency:\u003c\/b\u003e Pale, yellow new growth at the top of the plant.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003ePrevention is far cheaper than cure. A few millilitres in every watering stops these problems before they start.\u003c\/p\u003e\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eCalcium, magnesium and nitrogen:\u003c\/b\u003e Builds strong cell walls, keeps leaves deep green and supports chlorophyll production.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eChelated iron:\u003c\/b\u003e A micronutrient that often runs short, in a form plants can absorb easily.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eImproves nutrient uptake:\u003c\/b\u003e Helps your plants move and use the rest of their feed more efficiently.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eRoot feed or foliar spray:\u003c\/b\u003e Feed it at the roots for prevention, or spray it on the leaves for a fast fix.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAll media:\u003c\/b\u003e Suitable for soil, coco and hydroponics, alongside any base nutrient.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHow to Use\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eRoot feed:\u003c\/b\u003e Add 1–2ml per litre to your watering can or reservoir. Use throughout vegetative and flowering growth.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eFoliar spray:\u003c\/b\u003e To correct a deficiency, mix 15ml per litre, adjust the pH to between 5 and 7, and spray onto the leaves once a week until the problem clears. Spray with the lights off or out of direct sun.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eHouseplants:\u003c\/b\u003e Start at the low end, around 1ml per litre in your watering can.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFeeding Schedule\u003c\/h3\u003e\n\u003cp\u003eShogun's official 2026 LED Coco \u0026amp; Terra feed chart recommends CalMag as a root treatment at \u003cstrong\u003e0.5–1ml per litre\u003c\/strong\u003e when you are watering with pure, distilled, RO or soft water. In moderately hard water (around EC 0.4) no extra CalMag is needed. With Samurai Terra Light Mix soils, Shogun advise always adding CalMag at 0.5–1ml per litre.\u003c\/p\u003e\n\u003cblockquote\u003e\n\u003cp\u003e\u003cb\u003e🌱 Rose's Pro-Tip:\u003c\/b\u003e Add CalMag to your water first and stir before anything else goes in. Concentrated calcium mixed straight into phosphorus-rich feeds can react and drop out of solution, and then neither does its job. Water first, CalMag second, base feed third, extras last. And remember CalMag contains nitrogen and raises your EC, so check your EC after mixing and adjust your base feed if needed.\u003c\/p\u003e\n\u003c\/blockquote\u003e\n\u003ch3\u003eWhich Size?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003e250ml:\u003c\/b\u003e A houseplant collection or a single small grow. Treats up to 250 litres of water at 1ml\/L.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003e1 Litre:\u003c\/b\u003e The everyday grower's bottle.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003e5 Litres:\u003c\/b\u003e Better value for regular coco and hydro growers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003e10 Litres:\u003c\/b\u003e Multi-tent and larger setups.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003e25 Litres:\u003c\/b\u003e The lowest cost per litre for big grows.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSyringe Only:\u003c\/b\u003e For measuring small doses accurately, rather than guessing.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cb\u003eCalcium (Ca):\u003c\/b\u003e 3.2%\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eMagnesium (Mg):\u003c\/b\u003e 1.2%\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eNitrogen (N):\u003c\/b\u003e 2.6%\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eIron (Fe):\u003c\/b\u003e 0.1%, chelated\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eRoot feed:\u003c\/b\u003e 1–2ml per litre\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eFoliar spray:\u003c\/b\u003e 15ml per litre, pH 5–7\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSuitable for:\u003c\/b\u003e Soil, coco, hydroponics and houseplants\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eSizes:\u003c\/b\u003e 250ml, 1L, 5L, 10L, 25L\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Shogun Fertilisers","offers":[{"title":"250ml","offer_id":50529542275418,"sku":"SGN-CLMG-250","price":12.95,"currency_code":"GBP","in_stock":true},{"title":"1 Litre","offer_id":49820947644762,"sku":"HYN-26751L","price":17.55,"currency_code":"GBP","in_stock":true},{"title":"5 Litres","offer_id":52212790755674,"sku":"SGN-CLMG-5L","price":49.95,"currency_code":"GBP","in_stock":true},{"title":"10 Litres","offer_id":49820947611994,"sku":"HYN-266310L","price":84.95,"currency_code":"GBP","in_stock":true},{"title":"25 Litres","offer_id":54932139999578,"sku":"SGN-CLMG-25L","price":189.95,"currency_code":"GBP","in_stock":true},{"title":"Syringe Only","offer_id":51282440487258,"sku":"BFH-SYRINGE-SH7","price":3.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0774\/9861\/4106\/files\/rn-image_picker_lib_temp_c34b381c-7b72-4203-9108-589a14e9ee32.png?v=1791498307","url":"https:\/\/blackflaghorticulture.com\/pl\/products\/shogun-calmag","provider":"Black Flag Horticulture","version":"1.0","type":"link"}