Cannabis Feeding Schedule: Dosage, EC, and Tracking by Growth Stage
Cannabis feeding goes wrong in two directions: giving too much too early, and having no record of what you did when something looks wrong three weeks later. A feeding schedule solves both — it ramps nutrient strength to match the plant's actual uptake capacity at each stage, and it turns every dose into data you can compare against symptoms afterwards. This guide is about building and tracking that schedule, not about reading deficiency symptoms themselves.
Seedlings: feed the medium almost nothing
A seedling's uptake is tiny, and its tolerance for error is smaller. For the first week or two, plain water is the correct feed; after that, most growers begin at quarter to half strength and ramp up only as true leaf area expands. The trigger for increasing strength is the size of the plant, not the number of days elapsed — a slow seedling fed on the calendar of a fast one gets burned tips and a stall on top of whatever was already slowing it. The medium changes the picture too: amended soils often carry enough nutrition for the first several weeks with nothing added, while inert soilless mixes like coco need light feeding almost from the start, just at very low concentrations. What all approaches share is restraint at the beginning — an overfed seedling is far harder to fix than a slightly underfed one, because salt-damaged root tips have to be regrown rather than rinsed.
Veg to flower: how the recipe shifts
In vegetative growth the plant is building stems and leaves, so the feed stays moderate in strength and weighted toward nitrogen, with commonly cited EC starting points in the range of roughly 0.8 to 1.2 in coco and hydro — grower practice rather than a research threshold, and lower in soil, where the medium itself contributes. When flowering begins, total demand rises: the plant is filling buds with mass at the fastest rate of the cycle, and EC typically climbs into the 1.2 to 1.6 range in inert media, with the ratio shifting toward phosphorus and potassium while nitrogen is tapered down — proportionally, not to zero, because the plant still needs it for foliage it keeps. These figures are starting points that every grower adjusts against their water source, medium, and the plant's response; the pattern that matters is the direction of travel — strength and total dose rising through flower, composition moving toward bloom elements.
EC and runoff: the numbers that move before symptoms do
Measuring the EC of what goes in is only half the picture; the EC of what comes out the bottom tells you what is happening in the root zone. Runoff EC climbing steadily over successive waterings means salts are accumulating faster than the plant can use them — the precursor to tip burn and lockout that will only become visible on the leaves days or weeks later. Runoff EC falling well below input EC means the plant is drawing nutrients faster than water, which is informative too, especially in flower when demand peaks. Pairing EC with a runoff pH reading matters just as much, because an element can be fully present in the medium and still unavailable if pH has drifted out of range — the deficiency and the pH problem look identical from above. Measuring both at every feed takes about a minute, and the trend across a week is what carries the information, not any single reading.
Why the written history matters when trouble appears
Leaf symptoms lag their cause by days to weeks, which is why troubleshooting without records collapses into guessing. Take a plant that develops spotted, browning leaf edges in week five of flower: was it the strong feed in week three, a pH drift that started when the reservoir ran warm, a watering that got missed during a heat spike, or the natural senescence of an aggressive flowering plant? With a dated log of doses, EC, pH, and watering events, the answer is a comparison; without one, it is a debate with yourself. A written schedule drawn up before the cycle also serves as a guardrail during it — mid-cycle improvisation, usually prompted by a plant looking slightly unhappy, is where most accidental overdoses begin. And the record compounds across cycles: the same cultivar grown at a different EC next run is only a useful experiment if this run's feeding was written down.
How GrowScope helps
GrowScope's feeding tracker records each dose with its EC and pH readings, so the schedule you planned and the schedule you actually ran stay visible side by side. When a symptom appears weeks into flower, the feeding history lets you line up the doses that preceded it instead of reconstructing the timeline from memory — and the same records carry into the next cycle for a direct comparison at matching weeks.
Key takeaway
Ramp feed strength with the plant — almost nothing for seedlings, moderate and nitrogen-forward in veg, higher EC with more phosphorus and potassium in flower — and log every dose with its EC and pH, because the record is what lets you trace a symptom back to its real cause weeks later.