Enter your fertilizer's N-P-K, your container, and how strong to feed. We'll tell you how much to add. Feeding through a siphon mixer or injector instead? Switch the mode to get the concentrate for the injector's ratio.
About this tool: Simple Fertilizer CalculatorRelated Tools
Convert between EC, CF and ppm (500, 640 and 700 scales), with target strength by crop stage.
Open the converterHow much acid or base to add to reach your target pH, based on your water's hardness and alkalinity.
Open the calculatorEnter your water test results to see whether the water suits irrigation and how to treat it.
Open the analyzerMix media by ratio and see the blend's bulk density, porosity and water-holding capacity.
Open the calculatorThey are percentages by weight, so 10 lb of 10-10-10 holds 1 lb of each. But P is phosphate (actual phosphorus is 44% of it) and K is potash (actual potassium is 83%). A historical convention from reporting nutrients as oxides. It matters the moment you compare a label against a soil test.
A "Part A / Part B" system is formulated to be used together, so each part does not get dosed to the full target on its own; most carry little or none of at least one nutrient, and dosing one alone would overshoot the others. Instead, the parts are blended in the mix ratio you set (equal parts by default), and that combined blend is what's dosed to your target strength. Each part's own amount is then that total split back out by its share of the mix.
A spoon measures volume, a rate is a weight. Fine for houseplants; weigh it for a target ppm.
Salts pull water out of roots: scorched edges, wilting in damp compost, white crust. For containers, weak and often.
A pot is a closed system, so salts build up even when every dose was correct. Leach monthly: plain water until it runs freely out, and discard it.