Short answer. Good growers don't just turn the whole feed up or down. They move single elements: nitrogen tapered towards zero in the last 3–4 weeks, less ammonium after the flip, a little extra calcium through the stretch, small magnesium, boron and zinc bumps in flower, silicon in veg. Most of these are Grower practice: sensible, widely used, and barely tested. Two popular tricks are flatly contradicted by controlled cannabis trials: more phosphorus above about 30–60 mg/L and potassium ramps above about 250 mg/L did not raise yield or cannabinoids [3][4][5][6]. Sugars and molasses do nothing useful in mineral hydro. GenetixBay's own rule is simple: taper nitrogen, don't flush, keep everything else fed. A bottled 2-part can't do that; single salts or per-element dosing (what Jardin is built for) can.
How to read this article
Every trick below is a change from a base feed, not a recipe on its own. The base is the flower recipe in building a feed by stage: roughly N 150, P 50, K 250, Ca 150, Mg 55, S 115, Fe 2.5, Mn 0.5, Zn 0.3, B 0.4, Cu 0.08, Mo 0.04 mg/L at about 1.8–2.0 mS/cm. All amounts are mg/L (ppm by mass of the element) in the solution going to the roots. Salt percentages are in hydroponic salts explained; 1 g/L of a salt gives (percent × 10) mg/L of each element.
Two rules before you touch anything:
- Change one thing at a time and write it down. If you move N, K and Mg in the same week, you'll never know which one did what.
- Every cation you add competes with the others. Raising K pushes down Ca and Mg uptake; raising Mg or Ca pushes down K; ammonium pushes down all three. See nutrient antagonism.
The tricks at a glance
| Trick | Stage | Change from base | Evidence |
|---|---|---|---|
| N taper | Last 3–4 weeks | N stepped down to ~25 % then 0–20 mg/L; everything else unchanged | Grower practice (house approach); N/potency trade-off Supported [1] |
| Lower ammonium share | Flip onwards | NH₄ 10–20 % of N in veg → ≤10 % in flower | Supported [2] |
| "More P in flower" / PK weeks | Mid flower | P raised to 80–150+ mg/L | Myth beyond ~30–60 mg/L [3][4][5][6] |
| K ramp | Mid–late flower | K 250 → 300–400 mg/L | Contested: no yield response 60–340 mg/L [6] |
| Extra Ca in the stretch | Flower wk 1–3 | Ca 150 → 170–190 mg/L | Grower practice |
| N-free Ca source late | Taper weeks | Swap calcium nitrate for gypsum / a little CaCl₂ | Established chemistry; needed for the taper |
| Late Mg bump | Flower wk 5–end | Mg 55 → 65–75 mg/L | Grower practice; Mg–cannabinoid link Supported (one lab) |
| Extra S for aroma | Mid–late flower | S 115 → 150–200 mg/L | Grower practice, untested; "S for terpenes" Myth as a mechanism |
| Si in veg, stop in flower | Veg → mid flower | 20–50 mg/L Si, then 0 | Grower practice; stopping or keeping both untested |
| Fe chelate by pH | Any | EDTA / DTPA / EDDHA by root-zone pH | Established |
| B and Zn bump | Flower | B 0.4 → 0.5–0.6; Zn 0.3 → 0.4–0.5 | Grower practice |
| Mn, Mo, Cu | Any | Don't push | Caution: narrow windows |
| Cl, Na | Any | Keep low (Cl < 50–70, Na < 50) | Supported |
| Crop-steering EC ramp | Flip, late flower | Input EC up 0.4–0.8 mS/cm for generative steer | Grower practice |
| Late-flower EC drop | Last 1–2 weeks | Whole feed −20–40 % | Grower practice; inferior to an N-only taper |
| Molasses / sugars | Flower | 1–5 mL/L | Feeds soil microbes only, not the plant; Myth for the plant, harmful in hydro |
| Amino acids, fulvic/humic | Any | Label rate | Contested |
| Cold nights, darkness, drought | Last 1–2 weeks | Non-nutrient | Cold: colour real, terpene/resin gain Myth; darkness Myth; mild drought Supported, house-endorsed |
Nitrogen
1. The late-flower N taper
What and when. From about 4 weeks before harvest, step N down: ~75 % of late-flower N at week −3, ~50 % at −2, ~25 % at −1, 0–20 mg/L in the final days. P, K, Ca, Mg, S and micros stay at normal late-flower strength.
Claimed benefit and mechanism. Lower N late in flower shifts the plant from building leaf and protein towards secondary metabolism and senescence of the fan leaves. In a controlled cannabis trial, higher N suppressed cannabinoid and terpenoid concentrations while inflorescence yield rose with N up to about 160 mg/L [1]. So less N trades a little bulk for a little potency percentage. The taper puts that trade to deliberate use at the stage when the plant has finished building its canopy.
Evidence. The N/potency trade-off: Supported (one controlled trial [1]). The taper ramp itself: Grower practice, widely recommended by experienced growers, not tested as a ramp. It is the GenetixBay house approach, and the reason Jardin doses per element.
Risks. Start too early (more than ~4 weeks out) and you cut yield, because the plant still needs N to fill flowers. Fan leaves will yellow from the bottom; that's expected. Purple stems and leaves at this stage are mostly genetics and cold, not a sign to stop.
With single salts. Drop calcium nitrate and potassium nitrate step by step. Take K from potassium sulfate and MKP, and Ca from an N-free source (trick 6). Full table and reasoning: nitrogen. Why not to flush instead: the flush debate. Pre-harvest flushing is a Myth, and a harmful one: it starves the plant while it is packing on its final weight and resin.
2. N form: the ammonium share
What and when. Run 10–20 % of total N as ammonium (NH₄⁺) in veg, then cut to ≤10 % from the flip and towards 0–5 % in late flower.
Claimed benefit and mechanism. Two things. pH: nitrate uptake makes roots release hydroxide and bicarbonate, so the root zone pH climbs; ammonium uptake releases protons and pulls pH down. A small ammonium share balances the two and holds pH steady in hydro without constant acid [10]. Quality: in a controlled cannabis trial (200 mg/L N, 0–100 % NH₄), cannabinoids were highest under pure nitrate; 10–30 % NH₄ was tolerated, 50 % cut yield by 46 % and showed toxicity, 100 % killed the plants [2].
Evidence. Supported (one rigorous cannabis trial [2], consistent with greenhouse practice [10]). The veg 10–20 % / flower ≤10 % split is Grower practice built on that.
Risks and antagonisms. Ammonium competes with K⁺, Ca²⁺ and Mg²⁺ for uptake. Too much gives Ca/Mg/K-shortage symptoms on a well-fed plant and a sliding pH. Cutting ammonium in flower means pH will drift up faster; plan for more pH-down, which itself adds N (nitric acid), P (phosphoric) or S (sulfuric). Count it.
With single salts. Greenhouse calcium nitrate already supplies about 7 % of its N as ammonium. To add more in veg, use small amounts of MAP or ammonium nitrate. In flower, use only calcium nitrate and potassium nitrate, and use sulfuric or phosphoric acid for pH-down during the taper so you're not sneaking N back in.
Phosphorus
3. "More P in flower" and bloom boosters
What growers do. Raise P from about 50 to 80–150 mg/L or more in mid flower, often as a "PK week" with a concentrated booster.
Claimed benefit. Bigger, denser flowers, because P is in ATP and "flowering needs phosphorus".
What the research says. It doesn't work above moderate P. Four independent controlled trials agree: - Shiponi and Bernstein tested 5–90 mg/L P in two cultivars: 30 mg/L gave about 80 % of maximum yield, flower P stopped rising above 30 mg/L, and cannabinoid concentration was highest below 30 mg/L, falling as yield rose (largely a dilution effect) [3]. - Westmoreland and Bugbee tested 25, 50 and 75 mg/L P: no significant effect on flower yield or cannabinoid concentration, but significantly more P in the leachate. Leaves took up 35 % more P and flowers 11 % more, with nothing to show for it [4]. - Hershkowitz et al. found the same again, and that raising overall nutrient concentration did not raise yield or cannabinoids either [5]. - Bevan et al. predicted a flower optimum near 59 mg/L P in deep-water culture [6].
Evidence. "More P = bigger buds" beyond ~30–60 mg/L: Myth. The yield plateau: Established (four trials). See "bloom boosters": what's real and phosphorus.
Risks and antagonisms. More runoff P (an environmental cost and money down the drain), and higher salinity. High P inducing Zn and Fe deficiency is well known in other crops [10]; in cannabis it is possible but not shown: the Shiponi and Bernstein ionome data didn't show a clear fall in flower Zn or Fe at 90 mg/L P [3]. Calcium phosphate also precipitates in concentrates and in high-pH solution. See nutrient antagonism.
With single salts. Don't add P. If you want a flower P setting, hold 40–60 mg/L from MKP. During the N taper, MKP and phosphoric acid are your N-free P sources, so the taper doesn't touch P.
Potassium
4. The K ramp and the K:Ca:Mg balance
What growers do. Raise K from about 250 to 300–400 mg/L from mid flower (weeks 4–8), usually with potassium sulfate or a PK booster.
Claimed benefit and mechanism. K drives sugar transport into flowers, stomatal control and water relations, so more K should mean denser, heavier buds.
What the research says. In a flowering deep-water trial, yield showed no response to K anywhere between 60 and 340 mg/L [6]. One trial, one cultivar, but it's the only dose-response data in flower, and it doesn't support the ramp.
Evidence. K ramp for yield: Contested (strong grower lore; the one controlled trial found nothing [6]). K–Ca–Mg competition: Established in plant nutrition [10].
Risks and antagonisms. This is the real danger of the trick. K, Ca and Mg compete for uptake; pushing K above ~300 mg/L is a common cause of induced Mg deficiency (interveinal yellowing on older leaves) and Ca problems in late flower. Keep the cations balanced. A workable rule for soilless flower feeds, in meq/L: K about 5–7, Ca about 7–9, Mg about 3.5–5, i.e. Ca at or above K in charge terms. By mass, that is roughly K 200–270, Ca 140–180, Mg 45–60 mg/L. If you raise K, raise Mg a little with it (trick 7). See potassium and nutrient antagonism.
With single salts. If you want a modest K lift, add potassium sulfate: 0.11 g/L adds about 50 mg/L K and 20 mg/L S. During the N taper, K comes from potassium sulfate and MKP instead of potassium nitrate, which keeps K steady while N falls.
Calcium
5. Extra Ca through the stretch and early flower
What and when. Raise Ca from 150 to 170–190 mg/L in flower weeks 1–3, when the plant can double in height.
Claimed benefit and mechanism. Ca builds cell walls and membranes, and fast stretch growth means a lot of new wall. Ca moves only in the transpiration stream and can't be moved from old leaves, so growers front-load it.
Evidence. Grower practice. No cannabis Ca dose-response study exists. The mechanism is sound; whether the extra 20–40 mg/L matters is untested. Most stretch-time "Ca deficiency" is a delivery problem (low transpiration from high RH, cold or damaged roots, too much K, Mg or NH₄), not an empty tank. Fix VPD and roots first. See calcium.
Risks. More calcium nitrate also means more N at a time when the stretch is already leafy. Ca competes with Mg and K. The idea that LEDs create a need for extra Cal-Mag is a Myth (house position); demand is cultivar-, water- and medium-driven (Cal-Mag).
With single salts. 0.1 g/L calcium nitrate adds about 19 mg/L Ca and 16 mg/L N. If you don't want the N, use gypsum (below).
6. Switching to an N-free Ca source late
What and when. During the N taper, replace calcium nitrate with an N-free calcium source so Ca stays at 130–180 mg/L while N falls.
Why. Calcium nitrate is the main Ca source in nearly every feed. Cut it to cut N and you cut Ca too, in the weeks when the flowers are still building tissue. Without this switch, a taper turns into a Ca starvation.
Evidence. The chemistry is Established; the need follows directly from the taper.
Options and limits. - Calcium sulfate (gypsum, CaSO₄·2H₂O, ≈23 % Ca, ≈18.6 % S). 0.6 g/L gives about 140 mg/L Ca and 110 mg/L S. It dissolves only to about 2 g/L and slowly, so it can't go in a concentrate. Dissolve it straight into the final solution or dose it from a stirred slurry. It roughly doubles S; with Epsom and potassium sulfate also present, total S can pass 250 mg/L. That's tolerated by most crops but raises EC, so trim potassium sulfate if needed. - Calcium chloride (CaCl₂·2H₂O, 27 % Ca, 48 % Cl). Small doses only. 50 mg/L Cl brings just ~28 mg/L Ca, so use it to top up, not as the main source. Keep total Cl below ~50–70 mg/L (chloride). - A blend works best: gypsum for the bulk, a little CaCl₂ to fine-tune.
Magnesium
7. The late-flower Mg bump
What and when. Raise Mg from about 55 to 65–75 mg/L from flower week 5 to harvest.
Claimed benefit and mechanism. Mg is the centre of chlorophyll and activates the enzymes that fix carbon. Growers claim it keeps upper fans green longer, supports resin, and prevents the late-flower Mg fade. Magnesium supply did change cannabinoid and terpene production in Bernstein's lab (see magnesium); the veg optimum is 35–70 mg/L [7].
Evidence. Grower practice. The bump itself hasn't been tested in flower. The claim that it "raises THC" isn't shown; the claim that it prevents a late-flower Mg shortage is plausible, especially if K is high. Much late-flower Mg yellowing is induced by too much K or Ca, or low pH, not by too little Mg in the tank.
Risks. Mg competes with Ca and K. Above ~80–100 mg/L, Ca uptake suffers. Don't stack a Mg bump on a K ramp on a Ca bump: that's three cations all pushing up EC and each other.
With single salts. Epsom salt (magnesium sulfate heptahydrate): 0.1 g/L adds about 10 mg/L Mg and 13 mg/L S. Avoid magnesium nitrate during the taper: it adds N.
Sulfur
8. Extra S for aroma (terpenes and thiols)
What growers do. Raise S from about 115 to 150–200 mg/L in mid and late flower, for a louder nose.
Claimed benefit and mechanism. Two claims, and they need separating. - "S raises terpenes." Terpenes are hydrocarbons; they contain no sulfur. S feeds them only indirectly (enzymes, general metabolism). Once S is sufficient, there's no mechanism for more S to make more terpenes. Calling this a sulfur trick is a Myth as a mechanism. - "S raises skunk." This one has a real basis. The skunky note in cannabis comes from prenylated volatile sulfur compounds, chiefly 3-methyl-2-butene-1-thiol, which peak at maturity and in curing [8]. They do contain sulfur. But nobody has shown that feeding more sulfate raises them; they're present at tiny concentrations, so ordinary S supply is very unlikely to be limiting.
Evidence. Grower practice, untested. The compounds are Established [8]; the feeding link isn't. See sulfur.
Risks. Higher sulfate raises EC and can push Ca sulfate out of solution at high Ca. It does little harm at 150–200 mg/L, so it's a cheap experiment if you want to run one, side by side, same cultivar.
With single salts. Swap some potassium nitrate for potassium sulfate (more S, same K), or use Epsom salt. During the taper, S rises anyway as nitrates come out and sulfates go in.
Silicon
9. Si in veg; stop or keep in flower
What and when. 20–50 mg/L Si from potassium silicate in veg and early flower for stiffer stems; many growers stop around flower week 3–5, others run it to harvest.
Claimed benefit and mechanism. Silicon is deposited in cell walls and is beneficial in many crops against abiotic stress and some fungal disease. Cannabis does take it up (see silicon).
Evidence. Si as a beneficial element: Established in other crops. Yield, stem strength or quality benefits in cannabis: Grower practice, no direct cannabis trial found. Stopping in flower (claims about ash, trichomes or "hard" buds) and keeping it in flower are both Grower practice; neither has evidence behind it.
Risks. Potassium silicate is very alkaline and must go in first, into plain water, then pH-correct after everything else. It adds K, so count it against your K:Ca:Mg balance. It can precipitate with Ca in concentrates.
With single salts. Dose from a separate stock, first in the mix. If you stop it in flower, remember you've also removed some K.
Micronutrients
10. Iron chelate choice versus pH
Choose the chelate for your root-zone pH, not for the price: Fe-EDTA holds iron to about pH 6.5, Fe-DTPA to about 7.5, Fe-EDDHA to about 9 [10]. In hydro and coco at pH 5.6–6.2, EDTA or DTPA is fine; DTPA gives headroom if pH drifts up (likelier once ammonium is cut in flower). In soil or with hard, alkaline water, use EDDHA. Established. No ramp is needed: hold 1.5–3.0 mg/L Fe. Too much iron competes with Mn. See iron.
11. Boron and zinc during flowering
What. Small bumps from mid flower: B 0.4 → 0.5–0.6 mg/L, Zn 0.3 → 0.4–0.5 mg/L.
Claim. B is needed for pollen tubes, cell walls and sugar transport; Zn for auxin and enzyme function. Growers bump them for flower set and density.
Evidence. Grower practice. There's no cannabis flowering dose-response data. Sinsemilla doesn't make pollen tubes, so the classic boron-for-seed-set argument doesn't apply to unpollinated flowers.
Risks. Boron has the narrowest safe window of any nutrient: toxicity starts around 5 mg/L in solution in cannabis work, and leaf-tip burn can show well below that in recirculating systems where B accumulates. Never "bump" boron without measuring what's already there. Zn rises are mild but compete with Fe and Cu. See boron and zinc.
With single salts. Boric acid (17.5 % B) and zinc sulfate heptahydrate (22.7 % Zn) from a 1:1000 micro stock: 0.6 g boric acid in 1 L of stock, dosed at 1 mL/L, adds about 0.1 mg/L B.
12. Manganese, molybdenum and copper: caution
Don't play with these. Mn competes with Fe (and excess Fe or Zn suppresses Mn); above about 1 mg/L in solution you risk Fe-like yellowing. Mo is needed in hundredths of a mg/L; there's no benefit to more. Cu is toxic to roots at low concentrations; stay within 0.03–0.1 mg/L, and watch copper pipes and copper-based "root" products, which add more than you think. Hold all three at the base-feed levels in building a feed by stage.
13. Chloride and sodium: limits, not tricks
Keep Cl below about 50–70 mg/L and Na below about 50 mg/L in the feed, counting what your water brings. Both are salinity, not nutrition, at these levels. The one deliberate chloride use is small doses of calcium chloride during the N taper (trick 6). Sodium has no use; don't choose sodium-based pH-up or borate for a feed. See chloride and sodium.
Whole-feed strength
14. Crop-steering EC ramps
What. In drain-to-waste coco and rockwool, growers raise input EC from about 1.8–2.4 mS/cm (vegetative steer) to 2.4–3.2 mS/cm (generative steer) at the flip to hold back the stretch and again in late flower, and let substrate EC climb on purpose with bigger drybacks.
Mechanism and evidence. Water and salt stress shift assimilates towards generative growth; Supported in greenhouse horticulture, Grower practice in cannabis for the specific numbers. One cannabis study found controlled late-flower drought raised THCA and CBDA concentration by about 12–13 %. Raising nutrient concentration overall did not raise yield or cannabinoids in recirculating hydro [5]. So EC is a steering lever (water and salt stress), not a way to feed more. Full method: drain-to-waste and crop steering.
Risks. Tip burn, stalled growth and midday wilting from over-steering; substrate EC more than ~1.5 mS/cm above input needs a flush shot (root-zone management, not a pre-harvest flush).
15. Late-flower EC drops versus element-specific changes
What growers do. Cut the whole feed by 20–40 % in the last 1–2 weeks (for example 2.0 → 1.3 mS/cm), as a softer version of a flush.
What it actually does. It lowers N, which is the part you wanted, but it also cuts K, Ca, Mg, S and micros in the weeks when the flowers are still adding weight and resin. It's a blunt version of the N taper, and it sits on the same slope as flushing: the further you cut, the closer you get to starving the plant.
Evidence. Grower practice. There's no controlled evidence for a benefit; long nutrient withdrawal costs dry mass and cannabinoid yield (the flush debate).
GenetixBay position. Prefer the element-specific taper: N down, everything else at normal late-flower strength. Total EC will fall somewhat as nitrates come out; that's fine. The one legitimate reason for a lower input EC in late flower is a root zone that has run salty (high runoff or substrate EC); then lower the input to bring the root zone back into range, and fix the cause.
Additives
16. Carbohydrates: molasses and sugars
What growers do. 1–5 mL/L molasses or other sugars in the last weeks, to "sweeten" or "fatten" buds.
What's real. Molasses and sugars feed soil microbes only, not the plant (house position). Plants make their own sugars by photosynthesis and don't take meaningful amounts of sucrose up through the roots to feed flowers. Taste comes from terpenes, plant health, drying and curing, not from sugar in the root zone. In living soil, molasses does feed microbes, which may speed nutrient cycling; molasses also carries some K, Ca, Mg and S.
Evidence. "Molasses sweetens or fattens buds" or feeds the plant: Myth. As a microbial food in living soil: Grower practice; that's the only thing it does.
Risks. In hydro and recirculating systems, sugars feed bacteria and biofilm, strip dissolved oxygen and raise the risk of root rot. Don't use them there. See root browning in hydro.
17. Amino acids, fulvic and humic acids
What. Amino-acid biostimulants, fulvic acid and humic acid at label rates, sold for uptake, stress tolerance and "chelation".
What's real. Humic and fulvic substances do complex metals and can improve micronutrient availability in soil. In the one cannabis study, humic acid supplementation didn't raise cannabinoids; it reduced the natural spatial variability of cannabinoids through the plant [9]. Amino-acid products have very little cannabis data.
Evidence. Contested. Plausible in soil and soilless with poor micronutrient availability; no consistent yield or quality benefit shown in cannabis mineral feeds.
Risks. Amino acids are nitrogen. A label-rate amino product can add 10–30 mg/L N without your noticing, which quietly undoes an N taper. Count them. Humics stain roots and reservoirs and can feed microbes in hydro.
Non-nutrient finishing tricks
Briefly, because they aren't about elements:
- Cold nights in the last 1–2 weeks (for example 15–18 °C / 59–64 °F) bring out anthocyanin colour, but only in cultivars that carry it. The colour is real. Claims of more terpenes, flavour or resin from cold are a Myth until peer-reviewed data shows otherwise (house position). Too cold slows ripening. See temperature by stage.
- A 24–72 h dark period before harvest to "boost trichomes": Myth (house position). It cuts photosynthesis in the final, most critical days. See trichome ripeness.
Greenleaf's standing challenge: darkness before harvest. Putting plants in 24–72 h of darkness before the chop is a Myth, and the founder's verdict is "complete and utter nonsense": why cut photosynthesis in the most critical part of the life cycle, while the plant is still finishing its resin? For more than 20 years the founder has offered a standing challenge: find a peer-reviewed study showing a benefit (not a single-plant study, not biased or skewed) and a 50-pack of seeds is yours, no questions asked. Nobody has claimed it.
- Mild late-flower drought: one study found higher cannabinoid concentration; Supported (Caplan et al. 2019) and house-endorsed: the founder uses it, and some cultivars thrive when allowed to go a bit dry. Every cultivar responds differently, so test on one plant first (crop steering).
- Stem snapping (supercropping): Grower practice, house-endorsed; the founder does it all the time for better buds (HST and supercropping).
- UV-B: little or no visible difference in controlled trials; see light spectrum.
- Flushing: Myth, and harmful (the flush debate).
A worked late-flower example (single salts, RO water)
Base flower feed from feed by stage recipe 2, then the final week of the N taper with Ca held by gypsum. Per 1,000 L.
| Salt | Base (g) | Week −1 (g) | Week −1 supplies (mg/L) |
|---|---|---|---|
| Calcium nitrate | 790 | 200 | N 31, Ca 38 |
| Potassium nitrate | 200 | 0 | — |
| Gypsum (calcium sulfate dihydrate) | 0 | 500 | Ca 116, S 93 |
| MKP | 220 | 220 | P 50, K 63 |
| Magnesium sulfate heptahydrate | 560 | 600 | Mg 59, S 78 |
| Potassium sulfate | 240 | 420 | K 189, S 77 |
| Totals | N 150, P 50, K 248, Ca 150, Mg 55, S 117 | N 31, P 50, K 252, Ca 154, Mg 59, S 248 |
Micros unchanged. Dissolve the gypsum directly in the tank and stir well; it won't go into a concentrate. pH-down with phosphoric or sulfuric acid, not nitric. Measure EC; the arithmetic is a guide.
Common mistakes
- Running several tricks at once and crediting the wrong one.
- Ramping K and forgetting that it pushes Mg and Ca out.
- Stacking a PK booster on a complete base feed.
- "Tapering N" by diluting a 2-part, which cuts every element.
- Dropping calcium nitrate for the taper with no other Ca source.
- Adding amino acids or nitric acid during the taper and putting the N back in.
- Sugars in a recirculating system.
- Bumping boron without knowing what the water and the reservoir already hold.
Evidence
- N/potency trade-off: Supported [1]. N taper ramp: Grower practice (GenetixBay house approach).
- Ammonium ≤10–30 % of N; cannabinoids highest on nitrate: Supported [2]. NH₄ pH effects: Established [10].
- No yield or cannabinoid gain above ~30–60 mg/L P: Established (four trials [3][4][5][6]). "More P in flower": Myth. High P inducing Zn/Fe shortage: Established in other crops [10], not demonstrated in cannabis [3].
- K ramp for yield: Contested; no response 60–340 mg/L K in one flower trial [6]. K–Ca–Mg competition: Established [10].
- Extra Ca in stretch, late Mg bump, B/Zn bumps, Si on/off: Grower practice. Mg veg optimum 35–70 mg/L: Supported [7].
- Volatile sulfur compounds behind skunk aroma: Established [8]; S feeding raising them: untested. "S raises terpenes": Myth as a mechanism.
- Chelate pH limits: Established [10].
- Higher overall concentration not raising yield or cannabinoids: Supported [5]. Crop-steering EC numbers: Grower practice.
- Pre-harvest darkness: Myth (house position). Cold nights: colour real, terpene/resin gain Myth. Mild late drought: Supported, house-endorsed; cultivars vary. Supercropping: Grower practice, house-endorsed. UV-B: little or no visible difference.
- Molasses feeding the plant: Myth; it feeds soil microbes only. Molasses in hydro: harmful. Humic acid: Contested [9]. Amino acids: Contested, little data.
