Section 6:

Spectrum Science In Plain Language

This section explains what each channel does inside the plant so your team knows why the schedules work and where risk lives.

 

Full+Red — The backbone

What it is: Broad white with strong red content centered near 660 nm.
What it does: Drives photosynthesis efficiently, helps build structure, and powers flower site formation deeper in the canopy.

Key plant responses

• Higher carbon gain and carbohydrate supply to lowers.
• Tighter node stacking when intensity is matched to environment.
• More uniform flowers where top light falls off.

Where growers go wrong

• Turning it up faster than HVAC and irrigation can support. Watch VPD, runoff EC, and leaf posture after any increase.
• Trying to fix stretch with spectrum alone. First manage plant height with training, irrigation timing, and environment, then fine-tune spectrum.

Safe practice

• Keep Full+Red as the always-on channel during your photoperiod.
• Increase in small steps, verifying climate and irrigation capacity each time.

Far-Red (~730 nm) — The steering wheel

What it is: Narrow band around 730 nm that toggles the phytochrome system between active and inactive states.

Why it matters

• Controls shade responses. More FR relative to red tells plants they are shaded.
• Can accelerate certain metabolic clocks and shorten perceived day length at transitions.
• Pairs with red to increase electron transport efficiency for short windows, known as the Emerson effect.

Useful effects

• Smoother starts and finishes when pulsed at lights-on and lights-off.
• Deeper light penetration signal which improves development under the canopy.
• Late flower ripening cues that can help finish on time.

Risks

• Excess FR early flower lowers the Red:FR ratio toward shade-like signaling and can lengthen internodes.
• Multiple or long mid-day FR windows can create airy lowers if intensity is not balanced.

Safe practice

• Introduce as brief pulses at lights-on and lights-off first.
• Add only one short mid-day FR window after stability.
• If stretch increases, remove the lights-on pulse and keep only end-of-day.

UV — The finishing signal

What it is: Ultraviolet output in a controlled, low dose.

Why it matters

• Acts as a stress-like signal that plants interpret by thickening the cuticle and increasing secondary metabolite production.
• Can raise trichome density and support terpene expression when applied conservatively to mature flowers.

Risks

• Overexposure stalls growth, singes margins, or flattens aroma due to stress overshoot.
• Human exposure hazards. Only schedule windows when the room is empty.

Safe practice

• Use UV only in the last 2 to 3 weeks.
• Midday windows only, starting very short.
• Increase duration slowly and stop immediately at the first stress sign.
• Post a no-entry rule during UV windows and schedule UV only when the room is empty.

The Emerson effect — Red and Far-Red together

What it is: Short, deliberate pairing of red and FR that improves photosynthetic throughput compared to red alone.

How to apply it safely

• Keep Full+Red unchanged and add a single short mid-day FR window.
• Do not stack multiple mid-day FR windows until you have a week of stable response.
• Expect subtle gains, not dramatic jumps. The win is efficiency without stress.

Interactions with environment and nutrition

• Added photons increase demand for water and minerals. Adjust irrigation frequency first, then EC if needed, rather than jumping EC sharply.
• FR pulses can slightly change leaf temperature and transpiration patterns. Verify VPD and RH hold steady during and after windows.
• UV is not a substitute for balanced nutrition. If color or resin is not where you want it, check environment, irrigation, and genetics before adding more UV.

Quick decision rules

• Want tighter structure early flower: Reduce or delay FR, keep Full+Red steady, focus on environment and training.
• Lowers look underdeveloped: Raise Full+Red a small step or lower fixtures within the safe height window. Consider a short mid-day FR window only after stability.
• Finishing slow: Add or extend end-of-day FR by a few minutes. Do not add UV until flowers are mature and stress-free.
• Chasing more resin or aroma: Add a very short midday UV window in late flower. If edges react, cut duration in half.

Red:FR ratio in practice

• Think in windows, not all-day ratios under the canopy.
• Keep a strong red backbone all day.
• Use FR in short pulses for transition and one short mid-day efficiency window once the room proves stable.

What to measure and when

• During Full+Red changes: Lower-canopy temp, RH, VPD, runoff EC, posture.
• During FR windows: Internode behavior over 3 to 5 days, RH stability, finish timing.
• During UV windows: Edge condition, flower turgor, aroma intensity, daily growth rate.

With the science understood, Section 7 will translate this into channel-by-channel operating rules you can hand to the team.

 

Section 7:

Operating Each Channel

This section turns spectrum science into day-to-day rules you can hand to the team. Settings apply to both 4×4 and 5×5 areas using two fixtures in either perpendicular or parallel orientation.

 

Full+Red — Your always-on backbone

Role: Primary driver of photosynthesis and flower site development under the canopy.

Default use

• On for the full photoperiod, synced to top lights.
• Commissioning start: ~50 percent output.
• Adjustment cadence: Change in 10–15 percent steps, then observe for ~48 hours before adding any other spectrum change.

When to increase

• Lowers look flat or shadowed after proper placement.
• Runoff EC trends down while plants look hungry and posture is relaxed.
• Lower canopy temp is stable and RH/VPD stays in range after the last increase.

When to decrease

• Tip nip, edge curl, canoeing, or RH creep without irrigation issues.
• Runoff EC rises and leaves look “dry” despite adequate moisture.

Safe ranges by phase (starting points)

• Early flower (wk 1–2): 45–60 percent
• Mid flower (wk 3–6): 55–70 percent
• Late flower (wk 7+): 50–65 percent (hold steady; don’t chase last-minute jumps)

Do

• Mirror top-light sunrise/sunset ramps if used.
• Prioritize airflow and irrigation tuning before adding more intensity.
• Re-check 6 inch leaf clearance after every tuck/defol.

Don’t

• Don’t stack a Full+Red increase on the same day as a Far-Red or UV change.
• Don’t exceed environment capacity; solve RH and temp first.

Far-Red (~730 nm) — The steering wheel

Role: Phytochrome control for smoother starts/finishes and targeted efficiency bumps via short windows. Powerful but easy to overuse.

Default use (pulses first)

• Lights-on pulse: 5 minutes @ 20 percent

• End-of-day pulse: 5 minutes @ 20 percent

• Hold 48 hours and watch internodes. If stretch ticks up, remove the lights-on pulse and keep only end-of-day at 3–5 minutes.

Optional mid-day “Emerson” window (add only after stability)

• One mid-day window: 10 minutes @ 15 percent

• Keep Full+Red unchanged. Do not add more than one mid-day window until you’ve run a full week stable.

When to increase

• Finish is lagging and plants are structurally set.
• Lowers remain slightly under-developed even with adequate Full+Red and placement.

When to decrease

• Early flower stretch accelerates (longer internodes than usual).
• Lowers feel airy after adding mid-day FR.
• RH bumps during FR windows that HVAC can’t absorb.

Safe ranges by phase (windowed, not continuous)

• Early flower (wk 1–2): EOD only, 3–5 min @ 15–20 percent
• Mid flower (wk 3–6): EOD 5 min @ 15–20 percent; optional single mid-day 10 min @ 10–15 percent
• Late flower (wk 7+): EOD 5–8 min @ 15–25 percent; mid-day as above if stable

Do

• Think in pulses/windows, not all-day FR.
• Remove the lights-on pulse first if stretch appears.
• Re-verify RH/VPD during and right after FR windows.

Don’t

• Don’t stack multiple mid-day FR windows.
• Don’t use FR to fix training/height management problems; correct agronomy first.

UV — The finishing signal

Role: Low-dose hormetic cue to support trichome density and terpene expression in mature flowers.

Default use (late flower only)

• Start wk 7+ (or final 2–3 weeks depending on cultivar maturity).
• One mid-day window: 5 minutes @ 10 percent.
• After 3 days with zero stress, extend to 10 minutes. Rarely is more needed.

When to increase

• Flowers are mature and robust; zero edge singe or stall after the first window.
• Aroma is strong and stable; room climate easily holds VPD during the window.

When to decrease / stop

• Any edge singe, halted growth, or aroma flattening after a change.
• Human access conflicts. UV windows should coincide with no-entry periods.

Strict rules

• Never at lights-on or lights-off.
• Never while people are in the room without PPE.
• Post a no-entry rule during UV windows; schedule UV only mid-day.
• Never increase UV on the same day you change FR or Full+Red.

Safe ranges by phase

• Early/Mid flower: Off

• Late flower: 5–10 minutes mid-day @ 10 percent (short, conservative)

Quick presets (copy to Tri-Chan scenes)

Use these as baseline scenes for both 4×4 and 5×5 footprints (two fixtures).

• Scene: B50 (Baseline)

• • • Full+Red: 50 percent, full photoperiod (+ sunrise/sunset if used on top lights)
    • Far-Red: Off
    • UV: Off

• Scene: FR-Pulse

• • • Full+Red: same as B50
    • Far-Red: 5 min lights-on @ 20 percent; 5 min end-of-day @ 20 percent
    • UV: Off

• Scene: FR-Emerson

• • • Full+Red: same as B50
    • Far-Red: FR-Pulse + one mid-day 10 min @ 15 percent
    • UV: Off

• Scene: UV-Finish

• • Full+Red: same as current baseline
  • Far-Red: your current FR scene
  • UV: 5–10 min mid-day @ 10 percent

Label scenes cleanly and apply room-wide to avoid drift between zones.

 

Channel-specific troubleshooting

If lowers still underperform

• Check placement first (Section 4).
• Increase Full+Red +10 percent and hold 48 hours.
• If still lacking and structure is set, add one mid-day FR window (10 min @ 15 percent).

If stretch spikes in wk 1–2

• Remove the lights-on FR pulse; keep only EOD 3–5 min.
• If needed, drop Full+Red –10 percent for 24 hours while you rebalance VPD and irrigation.

If RH climbs during windows

• Add airflow across the lowers; increase dehu duty cycle.
• If unresolved, shorten FR mid-day window or reduce Full+Red –10 percent until stable.

If tips nip or edges dry after any change

• Undo the last change (scene rollback).
• Verify runoff EC and moisture. Prefer irrigation frequency adjustments before lowering EC.
• Re-introduce changes in smaller steps after stability returns.

Hand-off rules for the team

1. Change one channel at a time, in small steps.
2. Log scene, % settings, window durations, and observations.
3. Re-check lower-canopy climate and runoff EC after every change.
4. UV only in late flower, mid-day, short window, no people in room.
5. If anything looks off, revert to prior scene and notify a lead.

Section 8:

Baseline Daily Schedule

This gives you a safe, repeatable day plan you can load into Tri-Chan. It assumes a 12/12 flower cycle and two fixtures per 4×4 or 5×5 area, oriented perpendicular or parallel. Translate times to your room’s actual lights-on.

 

Notation

• T0 = top lights on
• T12 = top lights off
• Windows referenced by minutes from T0

Default daily schedule (Weeks 1–2, commissioning complete)

Purpose: establish under-canopy photosynthesis without driving stretch.

• Full+Red: T0 to T12 at 50 percent. If your top lights use sunrise/sunset, mirror a 10–15 min ramp.
• Far-Red: 5 min at T0 and 5 min at T12, both at 20 percent. No mid-day FR yet.
• UV: Off.

Daily checks: lower-canopy temp and RH during the first hour and the last hour. Internode behavior after 48 hours.

 

Mid-flower schedule (Weeks 3–6)

Purpose: keep lowers building while adding a single efficiency window.

• • Full+Red: T0 to T12 at 55–65 percent, hold steady once climate is stable.

• Far-Red:

• • Pulses: 5 min at T0 and 5 min at T12 at 20 percent
  • Mid-day Emerson window: 10 min at T0+360 min (hour 6) at 15 percent
• UV: Off.

Rules: Add only one mid-day FR window. If stretch increases or lowers get airy, remove the mid-day window first.

 

Late-flower schedule (Week 7 to finish)

Purpose: protect finish, add a short UV quality window.

• Full+Red: T0 to T12 at 50–60 percent. Do not chase late yield by increasing late.
• Far-Red: keep the mid-flower FR plan if plants and climate are stable.
• UV: one mid-day window at T0+360 min
  • Start 5 min at 10 percent for 3 days
  • If zero stress, extend to 10 min at 10 percent
  • Keep UV off at lights-on and lights-off

Human safety: no entry during UV windows without PPE.

 

Clock-based template you can Copy into Tri-Chan

Example for a 7:00 to 19:00 photoperiod. Adjust hours to match your room.

• 07:00–07:15 Top light sunrise (if used)
• 07:00 (T0) Full+Red to 50–60 percent for the day
• 07:00–07:05 Far-Red 20 percent (lights-on pulse)
• 13:00–13:10 Far-Red 15 percent (mid-day Emerson, add only after stability)
• 13:00–13:05 UV 10 percent (late flower only; extend to 10 min after 3 days stable)
• 18:45–19:00 Top light sunset (if used)
• 18:55–19:00 Far-Red 20 percent (end-of-day pulse)
• 19:00 (T12) Full+Red off, top lights off

Footprint notes for both 4×4 and 5×5

• Two fixtures per footprint. Start both at the same Full+Red level.
• If the center seam looks too bright, raise both fixtures 1–2 inches or drop Full+Red 10 percent and reassess.
• If corners lag, shift fixtures outward by 1–2 inches before increasing power.
  
• Maintain gentle airflow across the lower canopy.

What to log each day

• Scene used and any edits to % or window length
• Lower vs upper canopy temp and RH at 1 hour after T0 and 1 hour before T12
• Runoff EC and pH on a representative pot
• Notes on posture, internodes, edge condition, aroma

Decision gates built into the schedule

Advance only when the gate is passed. If not, hold or step back.

• Gate A, end of Week 1:

1. 1. 1. RH stable during FR pulses, no stretch spike
      2. If failed, remove lights-on FR pulse and retry after 48 hours

• Gate B, mid Week 3:

1. 1. 1. Lower sites building, no airy structure after FR pulses
      2. Add one mid-day FR window only if passed

• Gate C, start of Week 7:

1. 1. 1. Robust flowers, no recent stress markers, climate margins comfortable
      2. Add UV 5 min only if passed

• Gate D, 3 days after first UV:

1. 1. No edge singe, no stall, aroma strong
   2. Extend UV to 10 min only if passed

Fast rollbacks tied to the day plan

• Stretch in Weeks 1–2: remove lights-on FR, keep only end-of-day 3–5 min.
• RH spike during mid-day: shorten or remove the mid-day FR window, then restore once dehu margin improves.
• Any UV stress: cut UV duration in half or disable for 3–5 days, then reintroduce at the shorter window.

One-page summary

• Full+Red runs all day. Change in 10–15 percent steps, never on the same day as FR or UV changes.
• FR is pulses first. Add one mid-day window only after a full week of stability.
• UV is late flower only. Mid-day only. Start tiny. No entry during UV.
• If anything looks off, revert to the previous scene and log it.