Canna Hydro Feed Chart: Week-by-Week Dosing for Bigger Yields

Why the CANNA Hydro Feed Chart Is Worth Following Precisely

The CANNA Hydro feed chart is one of the most referenced nutrient schedules in run-to-waste hydroponics — and for good reason. CANNA Hydro Vega and Flores are two-part, pH-buffered formulas built specifically for recirculating and drain-to-waste systems. When you follow the chart with discipline — correct EC, correct pH, correct timing — you remove most of the guesswork that stalls yields. When you eyeball it, you get lockout, deficiencies, and wasted weeks.

Of 1,000 grow journals tracked on Grow Guide, 125 growers run top-feed drain-to-waste setups — the exact system CANNA Hydro is engineered for. This guide gives you the full canna hydro feed chart broken down week by week, with environmental targets and the practical reasoning behind each adjustment. Use the Grow Schedule Planner to map your specific start date against these phases.

System Setup Before You Start the Canna Hydro Feed Chart

Before you mix your first reservoir, sort out the hardware. CANNA Hydro is formulated for inert media — rockwool, clay pebbles, NFT channels. It is not designed for soil. If you're running coco coir, CANNA makes a separate Coco A&B line that handles the cation exchange properties of that medium. Using the Hydro line in coco leads to calcium and magnesium binding issues that no pH adjustment will fix.

• Water quality: Start with RO or low-ppm tap water (under 0.4 EC / ~200 ppm). Hard tap water inflates your baseline EC and skews ratios.
• Reservoir temperature: Keep it at 18–22°C. Above 24°C and dissolved oxygen drops; pathogens move in.
• EC meter calibration: Calibrate weekly with 1.41 mS/cm solution. Drift of 0.2 EC from an uncalibrated meter is enough to tip a plant into deficiency or toxicity.
• Mixing order: Always add A first, stir, then add B. Adding them together undiluted causes nutrient precipitation that won't redissolve.

The Full Canna Hydro Feed Chart: Vegetative Phase

The vegetative phase runs under 18/6 light (18 hours on, 6 hours off). CANNA Hydro Vega A&B is the backbone of this phase — it's nitrogen-heavy with elevated calcium to support fast structural growth. Keep humidity at 60–70% and canopy temperature at 28–30°C under HPS or 28–33°C under LED. VPD in this range typically sits around 0.8–1.2 kPa, which keeps stomata open and transpiration active without stressing young plants.

Veg Week 1 — Building the Root Zone

• Hydro Vega A&B: 15 ml per 10L
• Rhizotonic: 20 ml per 10L
• Cannazym: 25 ml per 10L
• Target EC: 1.3 mS/cm
• Target pH: 5.2

Rhizotonic is the key addition here — it's a root stimulator containing vitamins B1 and B2 that accelerates root zone establishment in rockwool or clay pebbles. Don't skip it in week 1. A strong root mass in the first 7–10 days translates directly to faster uptake for the rest of the grow. If you see slow growth and yellow cotyledons at this stage, use the Nutrient Deficiency Identifier before adjusting your mix.

Veg Week 2 — Ramping Up Nutrients

• Hydro Vega A&B: 25 ml per 10L
• Rhizotonic: 20 ml per 10L
• Cannazym: 25 ml per 10L
• Target EC: 1.7 mS/cm
• Target pH: 5.2

You're pushing EC up to 1.7 here as the root zone becomes established and the plant's uptake capacity increases. Monitor runoff EC daily. If runoff EC is climbing above 2.2 mS/cm, you have salt accumulation building — flush with plain pH-adjusted water until it drops. The vegetative phase can run as long as your canopy management requires. In the final two weeks before flipping to flower, you may keep running Vega while transitioning the light schedule to 12/12 to harden the plant before the flip. Check the cannabis indoor grow timeline guide if you're unsure when to flip.

Canna Hydro Feed Chart: Flowering Phase

When you flip to 12/12, you switch from Vega A&B to Flores A&B. Flores is phosphorus and potassium-dominant with reduced nitrogen — exactly what a cannabis plant needs when it stops building structure and starts packing on flowers. Notice that the pH target shifts upward significantly: from 5.2 in veg to 5.8–6.2 in flower. This is intentional. Phosphorus and potassium absorption peaks in the 6.0–6.5 range in hydroponic media, and you want that window open during peak bud development.

Flower Weeks 1–2 — Transition and Early Bud Set

• Hydro Flores A&B: 25–35 ml per 10L
• Cannazym: 25 ml per 10L
• Cannaboost: 20–40 ml per 10L
• Target EC: 1.2–1.6 mS/cm
• Target pH: 5.8–6.2

The EC actually drops slightly at the start of flower compared to late veg. This is correct — the plant is redirecting energy from roots and leaves toward reproductive output, and its metabolic demand for mineral nutrition briefly plateaus. Cannaboost is a carbohydrate-based flowering stimulator; run it at the lower end (20 ml/10L) in weeks 1–2, scaling toward 40 ml as flowering intensifies. Drop humidity to 50–60% now to reduce mould risk as canopy density increases.

Flower Week 3 — The PK 13/14 Peak

• Hydro Flores A&B: 25–35 ml per 10L
• Cannazym: 25 ml per 10L
• Cannaboost: 20–40 ml per 10L
• PK 13/14: 20 ml per 10L
• Target EC: 1.2–1.6 mS/cm
• Target pH: 5.8–6.2

PK 13/14 is CANNA's phosphorus/potassium spike supplement — it contains 13% phosphorous pentoxide (P₂O₅) and 14% potassium oxide (K₂O). Run it only during the peak bulking window, typically weeks 3–5 of flower depending on your strain's total flower time. Do not run PK 13/14 into late flower — excess phosphorus in the final two weeks stresses the plant and impairs the flush. Use it precisely. One week too many with PK 13/14 is one of the most common late-flower mistakes with this nutrient line.

Continue monitoring EC daily during this phase. Strains with large flowers and dense bud sites will drink more aggressively — you may need to top up the reservoir mid-week. Keep runoff EC within 0.2–0.3 mS/cm of your target input EC. Larger deviation in either direction signals either over-feeding or drought stress. Run the Yield Calculator around week 5 of flower to set a realistic harvest weight target based on your light output and canopy size.

Weeks 4–6 of Flower: Maintaining and Watching

After the PK 13/14 window closes, continue running Flores A&B at 25–35 ml/10L with Cannaboost. Your visual cues matter as much as the chart here. Watch for:

• Tip burn (brown leaf tips): EC is creeping too high — dilute your feed by 10–15%
• Pale or yellowing new growth: pH may have drifted above 6.5, locking out iron and manganese. Recheck and re-adjust.
• Slowed bud swell: Verify PPFD is hitting 800–1000 µmol/m²/s at canopy. Under-lit plants won't respond to nutrient increases. Check your setup with the Grow Light Calculator.

Drop humidity to 45–50% in the final three weeks of flower, particularly during the dark period. This is when botrytis (bud rot) strikes, and the CANNA chart can't protect you from that — environmental discipline does.

The Final Flush: Finishing the CANNA Hydro Feed Chart

The final week before harvest is a plain water flush at pH 5.8–6.2. Target EC of 0.0–0.4 mS/cm. This step clears residual mineral salts from the plant tissue and is considered standard practice for drain-to-waste hydro. Signs your flush is working: leaves begin yellowing from the bottom up as the plant mobilises stored nutrients — this is correct and expected. Trichomes should be checked daily under a jeweller's loupe or digital microscope. Harvest when 20–30% of trichomes have turned amber for a balanced cannabinoid profile. After harvest, use the Dry & Cure Timer to track your drying and curing milestones precisely.

Troubleshooting the CANNA Hydro Feed Chart

pH Keeps Drifting Up

In rockwool especially, new blocks can raise pH significantly in the first week. Pre-soak blocks in pH 5.5 water for 24 hours before planting. During the grow, CO₂ off-gassing from root respiration causes natural pH rise. Check pH every 24 hours and adjust with CANNA pH Down (phosphoric acid base). If pH is swinging more than 0.5 per day, your nutrient solution is too low in EC to buffer itself — check you're hitting target EC.

EC Is Correct but Plants Look Deficient

This is almost always a pH problem, not a nutrient quantity problem. At pH 5.5 or below, calcium and magnesium availability drops sharply. At pH above 6.5, iron, manganese, and zinc lock out. Cross-reference symptoms with the Nutrient Deficiency Identifier — it'll tell you which nutrient is implicated, then work backward to your pH log to find when it drifted.

Runoff EC Is Much Higher Than Input

Salt accumulation in the medium. Flush with two to three times the volume of plain water, check runoff EC after each pass, and resume feeding at 80% of your target dose for the first feed back. This is more common in clay pebbles that haven't been pre-washed than in rockwool. If you're logging feeds in a grow diary, this pattern becomes visible before it becomes a crisis.

Integrating CANNA Additives: What's Essential vs Optional

CANNA's additive lineup can feel overwhelming. Here's the honest breakdown for the Hydro line:

• Rhizotonic (veg, weeks 1–2): Worth using. Measurable root stimulation, especially in week 1 transplants.
• Cannazym: Enzyme formula that breaks down dead root material and improves substrate hygiene. Useful in recirculating systems. Less critical in drain-to-waste if you're replacing solution regularly.
• Cannaboost: Carbohydrate-based flowering stimulator. Users report denser bud structure. Run at mid-range (30 ml/10L) rather than maxing it out.
• PK 13/14: Essential during the bulking window. Do not skip it — the phosphorus and potassium demand during peak bud development significantly exceeds what Flores alone provides.
• Cannacure: Foliar spray for pest prevention. Use in veg only, never on open flowers.

If you're concerned about the cost of running the full additive stack, plug your total nutrient spend into the Cost Per Gram Calculator to see where your money is actually going relative to your expected yield. For growers earlier in their journey looking to nail seedling nutrition before moving to a full hydro schedule, the best nutrients for cannabis seedlings guide covers the transition period in detail.

References

1. CANNA Research (2024). CANNA Hydro Feeding Schedule — Official Product Guidance for Run-to-Waste Hydroponic Systems. Describes Vega and Flores dosing, EC targets, and additive integration for the Hydro line. glandorehydro.com/canna-feed-charts
2. Hyjo.co.uk (2024). CANNA Hydro Feed Chart — Week-by-Week Breakdown. Detailed breakdown of ml/10L doses, pH and EC targets across vegetative and flowering phases. hyjo.co.uk/feedcharts/canna/hydro
3. Sauce Growing (2024). CANNA Feeding Charts — Nutrient Schedules for Fertilizers. Covers CANNA Flores phase management, Cannaboost, and PK 13/14 timing. saucegrowing.be — CANNA feeding charts
4. Bugbee, B. (2021). Nutrient Management in Controlled Environments. Utah State University. Establishes evidence base for pH-dependent nutrient availability in soilless and hydroponic systems, including the phosphorus uptake window at pH 5.8–6.5. extension.usu.edu
5. Grow Guide Platform Data (2026). Internal grow journal analytics — 1,000 tracked grows. 125 of 1,000 logged grows use top-feed drain-to-waste systems, establishing the primary hydroponic user base for whom the CANNA Hydro line is relevant on this platform.