LED Layouts by Tent Size (2×2, 2×4, 3×3, 4×4)
Builder’s guide to LED tent layouts: recommended watts, bar/panel placement, hanging heights, and how to measure PPFD for uniform results.
Use this step-by-step to size watts, place bars and panels, and tune for even in popular tent sizes.
Step 1 — Pick your PPFD target
- Seedlings / clones: 150–300 µmol/m²/s
- Leafy herbs & greens: 300–500 µmol/m²/s
- Fruiting / flowering crops: 600–900 µmol/m²/s
Aim for ≥ 0.8 (min ÷ max) across the canopy.
Step 2 — Choose a modern watt range
Rule of thumb with efficient fixtures (≥2.7 µmol/J):
| Tent | Typical watts | Notes |
|---|---|---|
| 2×2 | 100–150 W | Compact panel or 2 mini bars |
| 2×4 | 200–320 W | Two long bars or a 4-bar unit |
| 3×3 | 250–400 W | 6–8 bars or panel plus sidebars |
| 4×4 | 400–650 W | 8–10 bars or two 240–320 W panels |
Step 3 — Place the fixtures
Keep 6–8″ from tent walls and drivers for airflow. Start with the heights below, then fine-tune.
2×2 layout
Height: 10–14″. Center a compact panel or run two mini bars in parallel.
2×4 layout
Height: 12–16″. Two long bars lengthwise, or a 4-bar frame evenly spaced.
3×3 layout
Height: 12–18″. Six–eight bars in a grid, or one panel plus sidebars to lift edges.
4×4 layout
Height: 14–20″. Eight–ten bars, or two mid-size panels with a slight overlap zone.
Step 4 — Measure & tweak
- Hot center: raise 2–4″ or dim 10–20%.
- Dark corners: drop 1–2″, add sidebars, or widen spacing.
- Too low overall: lower height or increase output.
Re-measure at the and repeat until the map evens out.
How to re-measure at the canopy
- Use a for true readings. Phone are OK for relative checks only.
- Set the probe at canopy height (top leaves). Turn fans down briefly to steady the reading.
- Measure a 9-point grid: center, mid-edges, and corners. Note min, max, and average.
- Calculate uniformity: min ÷ max. Target ≥ 0.8.
- Adjust: raise / lower 1–2″, dim 5–10%, or nudge bar spacing; then re-measure the same 9 points.
Tip: If you must convert lux → PPFD for white LEDs, treat it as an estimate only—each spectrum is different.
FAQs
What’s the best way to space LED bars?
Quick answer: split the area into equal lanes; keep 6–8″ from walls and 4–6″ between bars.
- 2×4: two long bars lengthwise or four bars evenly spaced.
- 3×3: 6–8 bars in a grid; leave a small center gap to reduce hotspots.
- 4×4: 8–10 bars; balance overlap zones to lift edges.
Can I mix different fixtures or wattages?
Yes—just match spectrum and dim to blend. Place the higher-output unit slightly higher or off-center.
- Panel + sidebars: dim the panel 10–20% to lift edges evenly.
- Two panels: offset the seam by 2–3″ to reduce a hot stripe.
- Always re-check a 9-point PPFD map after any change.
What height should I start at for each tent?
Starting points: 2×2: 10–14″, 2×4: 12–16″, 3×3: 12–18″, 4×4: 14–20″.
Lower for veg targets; raise for higher watts or to widen coverage. Adjust by 1–2″ and re-measure.
PPFD
Usable light at the canopy in µmol/m²/s.
Uniformity
How even the light is: lowest PPFD divided by highest. A result ≥ 0.8 is considered good.
Canopy
The top leaf layer of your plants. This is the reference height for all PPFD measurements.
PAR meter
A handheld sensor that measures photosynthetic light (PPFD) directly. Best tool for dialing in LEDs.
Lux app
A phone light meter. Useful for before/after comparisons, but lux → PPFD conversions are only rough estimates.
Not sure if your layout is really even?
Share your tent size, fixture model, and a quick PPFD or lux map. We’ll suggest bar spacing, height, and dimmer settings so you hit your targets without guesswork.