This is every guide we have published under Grow Lights 101, grouped by the question each one answers. The Grow Lights 101 page carries the handful we would hand a buyer first. This page carries the full set, including the later and more specialised pieces.
Two ways to use it. If commercial lighting is new to you, read the fundamentals in the order they are listed, because each one leans on the one before it. If you already have quotes or spec sheets in front of you, go straight to the comparisons and the operations playbooks, which assume you know the units and skip the definitions.
Learn the Basics
Start here. What the units mean, what the numbers should be, and how any figure quoted to you is checked before you rely on it.
| Guide | What it covers |
|---|---|
| PPFD & DLI for Cannabis: Targets by Stage | Seedling, veg and flower PPFD targets, the DLI arithmetic behind them, a week-by-week 12/12 flip plan, and the uniformity thresholds a PPFD map should clear. |
| How Many Fixtures Does My Room Need | Why the count comes from the bed layout and not from a photon target: counting the whole 4×4, 4×6 or 4×8 ft fixtures that fit down each row and spacing them evenly, leaving the aisles out of the canopy, then choosing the wattage step for the stage and the PPE bin for the budget. Worked 28 × 32 ft room, three plan-builds, hanging height, and the seven inputs to send a supplier. |
| Grow Light Efficacy: What µmol/J Really Tells You | What µmol/J measures, the electricity math underneath it, the DLC floor and the physical ceiling, and when paying more for a higher figure is the wrong buy. |
| Grow Light Terms: The 30 Every Buyer Meets First | The thirty terms that decide a lighting purchase, each with its unit, the conversation it belongs to, and the way a quoted number is checked. |
| Grow Room Terms: The Next 30 Every Buyer Meets | The room-side vocabulary: VPD, CO₂ enrichment, BTU per hour, sensible heat ratio, light saturation point and crop steering. |
| Legacy Grow Light Terms: HPS, Ballast and Candela | The legacy vocabulary, translated for a buyer reading an old spec sheet or planning an HID to LED retrofit: footcandles, watts per square foot, 1000W equivalent. |
Compare & Choose
For buyers with models and quotes in front of them: what separates two fixtures, two technologies and two spectral strategies.
| Guide | What it covers |
|---|---|
| LED vs HPS for Commercial Cannabis (2026 Data) | Efficacy, yield per square metre against yield per dollar, heat load and HVAC sizing, maintenance, payback, and the scenarios where HPS still makes sense. |
| Choosing a Spectrum for Cannabis Flower | Blue as the architecture dial, why a white base earns its place, red and the photobleaching risk, far-red scheduling, and the evidence state on UV. |
Certification marks sit outside this cluster. Which standards our models are listed against, and which model each listing covers, is set out on our certifications page.
Run It Right: Operations and Troubleshooting
For rooms already running: reading what the canopy is telling you, what the meter is charging, and what has to move after a light change.
| Guide | What it covers |
|---|---|
| Light Burn vs Nutrient Deficiency: Reading the Symptoms | The position, speed and feed-response triage, a two-way symptom decoder, and the canopy and root-zone readings that settle the argument before anyone touches the feed schedule. |
| Demand Charges and Lighting Load: How the Schedule Sets the Bill | Why lighting sets the demand peak, the schedule levers that flatten it, the load arithmetic behind a panel plan, and the energy-per-gram figures worth tracking. |
| After an LED Retrofit: Retuning the Room in the First 30 Days | Baseline readings before any setpoint moves, a week-by-week pass over temperature, irrigation and dehumidification, and when a ramp-in is actually needed. |
Which Guide Fits Your Room?
Send the room size, the ceiling height and the lights you run now, and our engineers come back with a fixture recommendation and indicative pricing.