# Should I use full-strength nutrients from the feeding chart?

> Usually not at first. Feeding charts are written as upper limits, often for hard water and vigorous plants. Start at about half to three-quarters of the chart and steer by EC instead: about 0.6-1.0 mS/cm for seedlings, 1.2-1.8 in veg and 1.6-2.2 in flower for coco and hydro, and 0.8-1.6 in soil. Raise strength only if runoff EC and leaves say the plant wants more.

- Canonical: https://genetixbay.com/knowledge/answers/full-strength-feeding-chart.html
- Topic: Nutrients · Type: How-to
- Evidence: Supported · Status: Draft: awaiting expert review
- Full article: [Building a cannabis feed by stage: ppm targets per element and how to hit them](https://genetixbay.com/knowledge/nutrients/feed-by-stage.md)
- Also asked as: Should I use half-strength nutrients? | Is the feeding chart too strong? | Should I start at quarter strength? | Why are my tips burning on the recommended dose? | Do I follow the bottle's feed schedule?
- Updated: 2026-10-31 · Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay Knowledge Base (genetixbay.com/knowledge)"

## Short answer

Not to start with. Treat a bottle's chart as a ceiling, begin at about half to three-quarters of it, and steer by [EC](https://genetixbay.com/knowledge/glossary/ec.md): roughly 0.6–1.0 [mS/cm](https://genetixbay.com/knowledge/glossary/ms-cm.md) for [seedlings](https://genetixbay.com/knowledge/glossary/seedling.md), 1.2–1.8 in veg and 1.6–2.2 in flower in [coco](https://genetixbay.com/knowledge/glossary/coco-coir.md) and hydro, and 0.8–1.6 in soil. Raise strength only when [runoff](https://genetixbay.com/knowledge/glossary/runoff.md) and new growth ask for it. *Supported.*

## Why

Charts are generic. They don't know your water, which may already carry 0.2–0.8 mS/cm, your medium or your cultivar. Full chart strength on top of [hard tap water](https://genetixbay.com/knowledge/glossary/tap-water.md) or fertilised soil is a common route to [tip burn](https://genetixbay.com/knowledge/glossary/nutrient-burn.md).

The research backs a moderate feed. In deep-flow hydro, doubling input from 2 to 4 mS/cm raised solution nutrients but not yield or [cannabinoids](https://genetixbay.com/knowledge/glossary/cannabinoid.md) [1]. Elevated phosphorus raised [leachate](https://genetixbay.com/knowledge/glossary/watering-to-runoff.md) P without improving yield or quality [2].

Charts quoting ppm are ambiguous: the same 1.0 mS/cm reads 500 ppm on one meter and 700 on another [3]. A 700-scale chart followed on a 500-scale meter overfeeds by about 40%.

## The numbers

| Stage | Coco / hydro EC (mS/cm) | Soil EC (mS/cm) | [ppm500](https://genetixbay.com/knowledge/glossary/ppm500.md) (coco/hydro) |
|---|---|---|---|
| Seedling, clone | 0.6–1.0 | Water only, weeks 1–4 | 300–500 |
| Veg | 1.2–1.8 | 0.8–1.6 | 600–900 |
| Flower | 1.6–2.2 | 0.8–1.6 | 800–1,100 |
| Late flower | 1.2–1.8 | 0.8–1.6 | 600–900 |

All values are total solution EC, including the water.

## What to do

1. Measure your water's EC.
2. Mix at half to three-quarters of the chart and read the EC.
3. Adjust to the stage target above, not the chart's number.
4. Check runoff EC; more than ~0.8–1.0 mS/cm above input means back off.
5. Step up 0.1–0.2 mS/cm at a time if lower leaves pale early.

## Common mistakes

- Running full chart plus every additive in the range.
- Following a ppm chart without knowing its scale.
- Ignoring the EC your tap water already brings.
- Reading dark green, [clawed leaves](https://genetixbay.com/knowledge/glossary/leaf-clawing.md) as "healthy and hungry".

## Related

- Full article: [Building a cannabis feed by stage](https://genetixbay.com/knowledge/nutrients/feed-by-stage.md)
- Answers: [feed every watering?](https://genetixbay.com/knowledge/answers/feed-every-watering.md) · [TDS vs EC meter](https://genetixbay.com/knowledge/answers/tds-meter-vs-ec-meter.md)
- Articles: [EC vs ppm scales](https://genetixbay.com/knowledge/ph-ec/ec-ppm-scales.md) · [brown, burnt tips](https://genetixbay.com/knowledge/diagnosis/brown-burnt-tips.md)
- Terms: [nutrient burn](https://genetixbay.com/knowledge/glossary/nutrient-burn.md) · [feed chart](https://genetixbay.com/knowledge/glossary/feed-chart.md)

## Follow-up questions

**What strength should I feed seedlings?** Feed cannabis seedlings and fresh clones at about EC 0.6-1.0 mS/cm in coco or hydro, which is often a quarter to half of a bottle's veg rate. In fresh potting soil, feed nothing for the first 2-4 weeks because the mix's starter charge already covers them. Raise strength gradually towards the veg range of 1.2-1.8 mS/cm as roots establish.

**How do I know if I'm feeding too strong?** You are feeding too strong when leaf tips burn and the burn creeps inward, leaves turn very dark and clawed, and runoff EC climbs more than about 0.8-1.0 mS/cm above what you pour in. Cut feed EC by 10-20%, check root-zone pH, and judge on new growth. Burnt tips never heal, so watch fresh leaves.

**Does feeding stronger give bigger yields?** No, feeding stronger does not give bigger cannabis yields beyond a moderate EC. In deep-flow hydro, doubling feed from 2 to 4 mS/cm raised solution nutrients but not yield or cannabinoids, and phosphorus above about 30-60 mg/L gave no gain in several trials. Extra strength mainly raises cost, salt build-up and the risk of tip burn.

## Sources

1. Hershkowitz JA, Westmoreland FM, Bugbee B, 2025. Elevated root-zone P and nutrient concentration do not increase yield or cannabinoids in medical cannabis. Frontiers in Plant Science 16:1433985. https://doi.org/10.3389/fpls.2025.1433985
2. Westmoreland FM, Bugbee B, 2022. Sustainable cannabis nutrition: elevated root-zone phosphorus significantly increases leachate P and does not improve yield or quality. Frontiers in Plant Science 13:1015652. https://doi.org/10.3389/fpls.2022.1015652
3. Prasad L, Meehan M, 2025. Using electrical conductivity and total dissolved solids meters to field test water quality. NDSU Extension WQ1923. https://www.ndsu.edu/agriculture/extension/publications/using-electrical-conductivity-and-total-dissolved-solids-meters-field-test