A feed chart is a table giving how much of each product to add per litre, and the expected EC, for each week or stage of growth. Manufacturers publish them for their product lines; experienced growers keep their own.
In practice
Manufacturer charts are often written for maximum product use and fast-feeding cultivars, and they frequently stack several additives on a base. Many growers start at half to three-quarters of chart strength and adjust by watching the plants and runoff EC. Charts are also system-specific: coco, rockwool and DWC need different strengths and frequencies than soil. Translating a chart into elemental ppm shows what it really delivers and makes comparisons possible.
Don't confuse with
- Recipe: a formula in grams of salt or mg/L of each element, independent of a product line.
- Feed by stage guide: general targets, not tied to a bottle.
Myth check
A feed chart is not evidence that every additive on it is needed. Trials show cannabis yield plateaus with moderate nutrient strength and phosphorus (Evidence: Established). Test your cultivar. See feed by stage.
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.Runoff is the water or nutrient solution that drains out of the bottom of a container after irrigation; growers test it to see what is happening in the root zone.Coco coir is a growing medium made from processed coconut husk, prized for holding water and air at once; it binds calcium and magnesium unless buffered.Rockwool is an inert growing medium spun from melted basalt rock into fibres, sold as plugs, cubes and slabs, that holds water and air in fixed proportions.DWC (deep water culture) suspends a plant's roots in an aerated nutrient solution, typically in a bucket with a net pot lid and an air stone.Ppm of an element means milligrams of that element per litre of solution (mg/L), the unit nutrient recipes use; it is not the ppm shown on an EC meter.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.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.Nutrient burn is browning and crisping of leaf tips, then margins, caused by a root-zone salt concentration (EC) higher than the plant can handle.A bloom booster is a high-phosphorus, high-potassium additive sold for flowering; cannabis trials show a P plateau, so past moderate levels it adds cost and runoff, not yield.
