The Best Grow Lights for Large Indoor Plants
Big plants are a geometry problem. The light has to be high enough to cover the canopy and still strong enough when it gets there.
By Scooter M. — An enthusiast who's genuinely into this. I read the manuals, compile the published specs, and do the math. No lab coat.
Published · How we pick
Photographs on this site are licensed stock and are illustrative of the fixture type. We do not own the units we write about.
How this page is funded: the buy links here are Amazon Associates links, and we earn a commission on qualifying purchases at no extra cost to you. We have not been paid to feature anything on this page, we accept no free product, and commission plays no part in the ranking. Full disclosure.
We have not tested these units. Everything below comes from the manufacturer’s own published specifications, or from arithmetic we have shown our working for. Where a figure is not published, we say so instead of estimating one. Read the method.
Quick picks
Efficacy is photons out per joule in. Where a manufacturer publishes it we quote theirs; where they publish photon output and wattage but not efficacy, we divide and label it as ours; where they publish neither, the cell says so rather than guessing. Tap a row for the full write-up.
| # | Product | Best for | Efficacy | Price |
|---|---|---|---|---|
| 1 |  Soltech Aspect Gen 2 The only fixture here you would willingly hang in a living room, and the only one publishing PPFD at three separate distances so it can actually be placed by the numbers. | Ceiling-mounted reach | 1.39 umol/J (ours) | |
| 2 |  AC Infinity IONBOARD S22 The highest published efficacy of any fixture here at 2.7 umol/J, on Samsung LM301H diodes, with dimming in real 20% steps rather than a vague knob. | Raw output at height | 2.7 umol/J | |
| 3 |  Mars Hydro TS 1000 The most photons of anything on this list, and one of only three fixtures here that publishes both PPF and efficacy so the claim can be checked against itself. | A very tall canopy | 2.3 umol/J | |
| 4 |  SANSI 36W BR30 Grow Light Bulb The rare grow bulb that publishes both PPF and a PPFD figure with the measurement distance attached, which is the only reason it can be sized honestly. | A floor lamp retrofit | 1.82 umol/J (ours) |
The reasoning
A six-foot fiddle leaf fig, a mature bird of paradise or an old monstera on a moss pole present a problem that small plants do not: the fixture has to be mounted high enough to cover the canopy, and light falls off sharply with distance. Most fixtures sold for houseplants are specified — where they are specified at all — at 12 inches, which tells you almost nothing about what happens at four feet.
The one fixture here that publishes the number that matters
Soltech is the only manufacturer on this site that publishes PPFD at several distances for the same fixture, and it is genuinely useful for exactly this case:
| Distance | Published PPFD | DLI at 12 h/day |
|---|---|---|
| 1 m (about 3 ft 3 in) | about 50 µmol/m²/s | 2.2 mol/m²/day |
| 4 ft | 34.9 µmol/m²/s | 1.5 mol/m²/day |
| 6 ft | 15.5 µmol/m²/s | 0.7 mol/m²/day |
The DLI column is ours — PPFD × 12 × 3600 ÷ 1,000,000 — and it is sobering. Even at 4 ft this fixture alone supplies roughly 1.5 mol/m²/day, which is below Iowa State University Extension’s 3-to-6 low-light band. Mounted at ceiling height over a tall plant, a single pendant is a supplement to daylight, not a replacement for it.
That is not a criticism of the product — it is the honest reading of numbers the manufacturer published, and Soltech deserves credit for publishing them at all. It is also the single most useful thing on this page, because it means a big plant in a genuinely dark room needs either multiple fixtures, a closer mounting point, or both.
What actually works for a tall plant
- Mount lower than instinct suggests, off to the side. A fixture at 2 to 3 ft angled across the canopy delivers far more than one at 6 ft directly above, and large plants tolerate side lighting well — they lean, so rotate the pot.
- Use two fixtures, not one bigger one. Two modest fixtures at opposite sides of a tall plant beat one at the ceiling, because both are closer and the canopy is lit from two directions.
- Light the leaves you have, not the pot. The productive foliage on a mature plant is the outer canopy. Aim there.
- A panel with a dimmer is a genuine option. At 3 to 4 ft a 100 W-class board still delivers usefully, and dimming lets you tune it down if the plant shows stress.
The AC Infinity IONBOARD S22 publishes 115 W at 2.7 µmol/J, which implies about 311 µmol/s of photon output (our arithmetic — AC Infinity does not publish PPF directly).
At 3 ft the light has spread well beyond the board’s stated 2 × 2 ft footprint. Assume it now covers about 4 × 4 ft — 16 sq ft, or 1.486 m².
311 ÷ 1.486 × 0.8 uniformity = about 167 µmol/m²/s. At 12 hours: DLI = 7.2 mol/m²/day, inside Iowa State’s 6-to-10 band for foliage and flowering houseplants.
The 4 × 4 ft spread at 3 ft is our estimate from beam geometry, not a published figure, and we have flagged it as such — AC Infinity does not publish a beam angle.
The mistake to avoid
Buying the biggest fixture and hanging it at the ceiling. The inverse-square relationship means the extra output largely disappears across the extra distance, and you have bought a 150 W running cost for a modest gain. Distance is the more powerful lever than wattage, and it is free. See how far a grow light should be from plants for the full treatment.
Every pick in full
Soltech Aspect Gen 2
PendantCeiling-mounted reach
The only fixture here you would willingly hang in a living room, and the only one publishing PPFD at three separate distances so it can actually be placed by the numbers.
What Soltech publishes
- Power draw
- 36 W (source)
- PPF (photon output)
- 50 umol/s (source)
- PPFD
- about 50 umol/m2/s at 1 m, 34.9 at 4 ft, 15.5 at 6 ft (source)
- Spectrum
- 3000 K warm white, CRI 98 (source)
- Dimming
- Yes, in-line dimmer 10-100% (source)
- Dimensions
- 3.5 x 3.5 x 6.2 inches (source)
- Rated life
- 50,000 hours (source)
Our arithmetic
- Efficacy, computed from the published figures: 1.39 umol/J
50 umol/s / 36 W = 1.39 umol/J. Roughly half the efficacy of a 2.7 umol/J board — the design premium is paid twice, once at purchase and again every month on the meter.
Who should skip it
Skip it if photons per watt is the metric that matters. At 50 umol/s from 36 W it is the least efficient fixture on this page, and much of the price is industrial design.
AC Infinity IONBOARD S22
LED panelRaw output at height
The highest published efficacy of any fixture here at 2.7 umol/J, on Samsung LM301H diodes, with dimming in real 20% steps rather than a vague knob.
What AC Infinity publishes
- Power draw
- 115 W (source)
- Efficacy
- 2.7 umol/J (source)
- PPFD
- 1098 PPFD (no measurement distance published) (source)
- Stated coverage
- 2 x 2 ft (source)
- Spectrum
- Samsung LM301H, plus 660 nm, 730 nm, 3000 K, 6500 K (source)
- Diodes
- 272 diodes (source)
- Dimming
- Yes, 0-100% in 20% increments (source)
- Dimensions
- 30.0 x 30.0 cm board, 1.1 cm thick (source)
- Rated life
- 50,000 hours (source)
Our arithmetic
- Photon output implied by the published wattage and efficacy: about 311 umol/s
115 W x 2.7 umol/J = 310.5 umol/s. AC Infinity does not print PPF directly, so this is our arithmetic from two figures it does print.
What AC Infinity does not publish
- PPF in umol/s — only efficacy is given, so photon output has to be derived
- The measurement distance for the 1098 PPFD figure, without which the number cannot be compared to anything
Who should skip it
Skip it if you want to place it by the numbers. AC Infinity prints 1098 PPFD with no measurement distance attached, which makes that figure impossible to use or compare.
Mars Hydro TS 1000
LED panelA very tall canopy
The most photons of anything on this list, and one of only three fixtures here that publishes both PPF and efficacy so the claim can be checked against itself.
What Mars Hydro publishes
- Power draw
- 150 W +/-5% at 100-277 V AC (source)
- PPF (photon output)
- 343 umol/s (source)
- Efficacy
- 2.3 umol/J (source)
- Stated coverage
- 2.5 x 2.5 ft vegetative, 2.3 x 2.3 ft flowering (source)
- Spectrum
- 660-665 nm, 730-740 nm, 3000 K, 5000 K (source)
- Diodes
- Bridgelux (source)
- Dimming
- Yes, 0-100% dimmer knob (source)
- Dimensions
- 406 x 326 x 50 mm (source)
Our arithmetic
- Average PPFD across its stated 2.5 x 2.5 ft vegetative footprint: about 470 umol/m2/s
2.5 ft x 2.5 ft = 6.25 sq ft = 0.581 m2. 343 umol/s divided by 0.581 m2 = 590 umol/m2/s at perfect uniformity; applying a 0.8 uniformity factor gives about 472 umol/m2/s average. - Electricity used at 14 hours a day for 30 days: 63.0 kWh a month
150 W x 14 h x 30 d / 1000 = 63.0 kWh.
Who should skip it
Skip it if you are lighting a bookshelf. 343 umol/s concentrated into a 2.5 ft square is far more light than a monstera wants, and you pay 150 W to deliver it.
SANSI 36W BR30 Grow Light Bulb
Grow bulbA floor lamp retrofit
The rare grow bulb that publishes both PPF and a PPFD figure with the measurement distance attached, which is the only reason it can be sized honestly.
What SANSI publishes
- Power draw
- 36 W (source)
- PPF (photon output)
- 65.6 umol/s (source)
- PPFD
- 265.58 umol/m2/s at 1 ft (source)
- Spectrum
- 4000 K, 400-780 nm, CRI close to 100 (source)
- Rated life
- 25,000 hours (source)
Our arithmetic
- Efficacy, computed from the published figures: 1.82 umol/J
65.6 umol/s / 36 W = 1.82 umol/J. That is roughly a third less efficient than the panels on this page — the price of a screw-in form factor. - Electricity used at 12 hours a day for 30 days: 12.96 kWh a month
36 W x 12 h x 30 d / 1000 = 12.96 kWh.
What SANSI does not publish
- Beam angle
- Fixture dimensions
Who should skip it
Skip it if you are lighting more than one plant. 65.6 umol/s is a small amount of light spread over a cone — it lights a single specimen, not a shelf.
Questions people actually ask
+What grow light do I need for a large indoor plant?
+Can a ceiling-mounted pendant light a six-foot plant?
+Should I light a tall plant from above or from the side?
Sources
- Soltech — Aspect Gen 2 published specifications — consulted September 2, 2026
- AC Infinity — IONBOARD S22 published specifications — consulted September 2, 2026
- Iowa State University Extension — Important Considerations for Providing Supplemental Light to Indoor Plants — consulted September 2, 2026
- Mars Hydro — TS 1000 published specification table — consulted September 2, 2026
- SANSI — BR30 36W grow light bulb product page — consulted September 2, 2026
Read next
Houseplants
The Best Grow Lights for Indoor Plants
Sized to a 3-10 mol/m2/day houseplant target rather than a grow-tent target, with running cost for each.
Coverage & Sizing
How Far Should a Grow Light Be From Plants?
The inverse-square rule, published PPFD-at-distance figures, and a by-plant table.
Houseplants
Grow Lights for Monstera
The 6-10 mol/m2/day target for monstera, what it means for fixture size, and the truth about fenestration.
Coverage & Sizing
PPFD Targets by Plant Type
Published light bands mapped to common indoor plants, with the DLI each implies.
Where this sits
This page belongs to Grow Lights for Houseplants and Winter. Every figure on it is either quoted from a named published source or derived in view — the full method is on our methodology page, and how the site is funded is on the affiliate disclosure.