Botanicare Feeding Schedule for Cannabis
Week-by-week Botanicare nutrient dosing for cannabis seedling through harvest.
Growing, buying or possessing cannabis and seeds is legal only in some places. Check the law where you live before acting on this information.
Botanicare is a reliable, widely available two- and three-part nutrient line used by thousands of North American growers. But the printed chart is a starting point, not gospel. Most growers run 50–75% of label strength and adjust by watching the plant and measuring runoff EC. No bottle turns a poor environment or weak genetics into a prize plant. Nutrients mainly prevent deficiency and toxicity.
What the Botanicare schedule is
Botanicare publishes feed charts for two main product lines used in cannabis: CNS17 (a concentrated three-part: Grow, Bloom, Ripe) and Pure Blend Pro (a two-part: Grow and Bloom, formulated with fish emulsion, humates, and kelp). The charts list weekly dosing in milliliters per gallon for each stage — propagation, vegetative growth, transition, early flower, peak flower, and ripening — plus optional supplements like Cal-Mag Plus, Liquid Karma, Hydroplex, and Sweet.
The schedules claim to work across all media (soil, coco coir, hydro, ebb and flow), which is convenient but means the printed numbers are a compromise. Coco coir, in particular, has zero nutrient holding capacity and requires different calcium and magnesium levels than soil or hydro. Cannabis-specific tuning is almost always required.
Why growers use Botanicare
Botanicare has been in the North American hydro retail market since the 1990s and remains stocked in most US grow shops [1]. Growers choose it for practical reasons:
- Forgiving chemistry. Pure Blend Pro contains fish, humates, and kelp derivatives that buffer pH swings and minor mistakes better than pure mineral salts.
- Simple lineups. Two- and three-part systems are easier to measure and mix than 8- or 10-bottle programs.
- Concentrated formulation. CNS17 is potent per milliliter, so a small volume goes a long way; cost per finished gallon is competitive.
- Wide availability. Stocked in most regional hydro retailers in the US and Canada.
What Botanicare is not: a substitute for light, genetics, environment, or grower experience. Yield is determined mostly by wattage, photoperiod, temperature, humidity, and plant genetics. Nutrients enable the plant to express that potential without deficiency or toxicity, but no bottle makes a weak environment or low-vigor strain into a champion.
When to start feeding
Seedlings and freshly rooted clones rely on stored reserves (cotyledons in seeds, mobile nutrients in cuttings) for the first 1–2 weeks. Starting nutrients too early risks salt burn and stunts growth.
Seedlings: Begin light feeding (¼ to ½ strength of the vegetative schedule on the chart) once the first true serrated leaves are fully expanded, typically 10–14 days from germination. Watch for pale new growth; if it appears, increase to half strength.
Rooted clones: Start light feeding once roots are visible and new growth has emerged, usually 7–10 days after transplant. In coco coir, add Cal-Mag from the start, as coco has a high cation exchange capacity and preferentially binds calcium and magnesium [2].
Coco coir growers: Coco holds no nutrients on its own and needs calcium and magnesium to buffer it. You may need to initiate a dilute Cal-Mag feed earlier than the chart suggests, even before the first true leaves are open [2].
Flushing before harvest: Stop nutrients 7–14 days before harvest and run plain pH-adjusted water. Whether flushing meaningfully improves smoke quality is disputed Disputed. A 2021 laboratory trial by Rx Green Technologies found no sensory or chemical difference between flushed and unflushed cannabis, though controlled studies remain limited.
How to run the schedule, step by step
- Test your water. Measure the EC and pH of your tap water or reverse osmosis (RO) water before you mix nutrients. If tap EC exceeds ~0.4 (approximately 200 ppm on the 500 scale), account for it in your target EC or use RO to start from zero.
- Start at 50–75% of chart strength. The Botanicare chart's full-strength columns are calibrated for ideal conditions and zero-EC starting water. Most growers find that running half to three-quarters strength avoids salt buildup and nutrient burn Anecdote. Begin conservative and increase only if the plant shows pale or slow new growth.
- Mix in order. Fill the reservoir with your starting water. Add Cal-Mag first (especially critical if using RO), then base nutrients (Grow or Bloom), then any supplements (Liquid Karma, Hydroplex, Sweet). Stir well between each addition to ensure homogeneity.
- Measure final EC. Common EC targets for cannabis in coco or hydro are seedlings 0.4–0.8 EC, vegetative 1.2–1.6 EC, and flower 1.6–2.2 EC [3]. These are general ranges; Botanicare-specific targets are not published in peer-reviewed trials.
- Adjust pH last. Target 5.8–6.2 for hydro and coco coir, 6.2–6.8 for soil [3]. Always pH after adding all nutrients and supplements, as nutrient solutions buffer pH and adding pH-down before nutrients will drift back up.
- Feed and check runoff. In coco, feed to approximately 10–20% runoff and immediately measure runoff EC. If runoff EC is significantly higher than input EC, salts are accumulating; cut the next feed to plain water or half-strength to allow the plant to draw down reserves.
- Transition at week 3 of flower. Switch from Grow to Bloom formula. If using CNS17 Ripe, introduce it in mid-to-late flower per the chart, again at reduced strength (50–75% of the printed dose).
- Taper in final weeks. The last 1–2 weeks before harvest, feed plain pH-adjusted water only, or very dilute Bloom (25% strength) if the plant shows yellowing.
Keep a detailed log. Record the date, input EC, input pH, runoff EC, runoff pH, and what you observed in the plant (new growth color, leaf shape, vigor). This single habit will teach you more about your specific setup than any published chart.
Common mistakes
- Running the chart at 100% without an EC meter. The most common cause of nutrient burn. The printed numbers assume ideal conditions and zero-starting EC. Without a meter, you cannot know if you are at 50% or 150% of intended strength.
- Skipping Cal-Mag in coco or with RO water. Coco coir has a very high cation exchange capacity and binds calcium and magnesium preferentially, causing rust spotting and interveinal yellowing within weeks if not supplemented [2].
- Stacking every supplement at once. Liquid Karma + Hydroplex + Sweet + Cal-Mag at full printed strength pushes EC into toxic territory very quickly. Pick one or two supplements you actually need (e.g., Cal-Mag in coco, Liquid Karma if you want carbs) and run them at reduced strength.
- Adjusting pH before adding all nutrients. Cal-Mag or base nutrients added after pH adjustment will shift pH back up. Always pH-adjust last, after all nutrients and supplements are mixed.
- Ignoring runoff. Input EC tells you what you fed; runoff EC tells you what accumulated in the root zone and what the plant used. Climbing runoff EC is a red flag for salt buildup, even if the plant looks okay today.
- Chasing terpenes with carbohydrate supplements. Botanicare Sweet and similar products are marketed as flavor enhancers, but no controlled trial has shown that any carbohydrate supplement changes the aroma or potency of finished cannabis No data. They may benefit plant physiology, but marketing claims about terpene enhancement are folklore.
Related techniques and alternatives
If Botanicare does not suit your setup or budget, comparable approaches include:
- General Hydroponics Feeding Schedule for Cannabis — a three-part mineral system (Flora Trio) with similar logic and wide availability.
- Jacks 321 — a dry salt formula (3 parts nitrogen, 2 parts phosphorus, 1 part potassium ratio) that is cheaper per gallon and more precise, but offers less chemical buffering and requires careful mixing.
- Living soil and top-dressing — replaces bottled feeding with pre-amended soil, compost, and organic amendments; eliminates the need to measure EC or mix nutrients.
- Coco-specific lines (Canna Coco A+B, House & Garden Cocos) — formulated specifically for coco's cation exchange chemistry and often include calcium and magnesium built in.
Regardless of brand, the underlying skills matter most: measuring EC accurately, managing pH, reading plant responses, and logging your inputs. These habits transfer across any nutrient system.
Sources
- Reported Maximum Yield Magazine. 'A Brief History of Hydroponic Nutrients.' Coverage of major nutrient brands including Botanicare.
- Peer-reviewed Caron J, Rivière LM, Guillemain G. (2005). 'Gas diffusion and air-filled porosity: Effect of some oversize fragments in growing media.' Canadian Journal of Soil Science, 85(1), 57–65.
- Book Cervantes J. (2015). The Cannabis Encyclopedia. Van Patten Publishing. Chapters on nutrients, electrical conductivity, and pH targets.
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