A mineral fertiliser, often called synthetic, is a manufactured or refined inorganic salt such as calcium nitrate, potassium nitrate, monopotassium phosphate or magnesium sulfate. It dissolves directly into ions such as nitrate, ammonium, phosphate, potassium, calcium, magnesium and sulfate, the same ions microbes release from organic matter.
In practice
Mineral feeds are the standard for hydroponics, coco and rockwool because they are precise, fully soluble, measurable by EC and do not foul lines. They give fast response but no buffer: mistakes show quickly, and the root zone does not hold reserves the way amended soil does. Their quality depends on recipe and management rather than on origin.
Don't confuse with
- "Chemical" as a scare word: everything in a feed is a chemical, organic or not.
- Organic fertiliser: nutrients released slowly by microbes.
- Plant growth regulators: synthetic hormones, a different category entirely.
Myth check
"Synthetic nutrients make harsh smoke" is not supported by controlled trials; harshness comes mainly from drying and curing. The plant mostly doesn't care where the ions come from (GenetixBay house position). See organic vs mineral and Mythbusters.
Calcium nitrate is the standard hydroponic calcium source, supplying about 19% calcium and 15.5% nitrogen, mostly as nitrate.Potassium nitrate (KNO3) is a soluble fertiliser salt supplying about 13% nitrogen as nitrate and 38% potassium, used in both veg and flower feeds.Monopotassium phosphate (MKP, KH2PO4) supplies about 22.7% phosphorus and 28.7% potassium with no nitrogen, and is the base of most PK boosters.Magnesium sulfate heptahydrate, sold as Epsom salt, is the common hydro magnesium source, supplying about 9.9% magnesium and 13% sulfur.Nitrate (NO3-) is the main form of nitrogen in hydroponic and soilless feeds; its uptake tends to push root-zone pH upward.Phosphate is the ionic form in which plants absorb phosphorus, mainly H2PO4- at the normal root-zone pH of 5.5-6.5.EC (electrical conductivity) measures how well a solution conducts electricity, a proxy for total dissolved salts; growers read it in mS/cm to gauge nutrient strength.An organic fertiliser supplies nutrients from plant, animal or mineral-rock sources that soil microbes must break down into ions before roots can absorb them.An A/B nutrient is a mineral feed split into two concentrates so that calcium (part A) is kept apart from sulfate and phosphate (part B), which would precipitate together.A stock solution is a concentrated nutrient mix, often 100x or 200x final strength, diluted into the reservoir; calcium and sulfate/phosphate stocks must stay separate.Per-element dosing builds a feed from individual salts or single-element stocks so each nutrient can be set independently, such as cutting nitrogen without cutting potassium.
