Sunco Grow Lights

We have not tested these fixtures. We own none of them and have measured none of them. What follows is the specification Sunco publishes, collected in one place, our own arithmetic run on top of it, and an explicit list of what Sunco does not publish.

Sunco sells mostly ordinary household and commercial lighting — shop lights, flood bulbs, downlights — with a small grow-light line called SuncoGrow sitting alongside it. That lineage shows up in the fixtures themselves, which are 4 ft linkable strips with a pull chain, and it shows up in the paperwork, which is written to the standards of general lighting rather than horticulture.

The one photon figure in the range

Almost every cheap 4 ft grow strip on the market publishes lumens, watts, a Kelvin number and nothing else. Sunco mostly does the same. But on one fixture it does something the rest of the category does not: the 4 ft 40 W model lists a PPF.

That single number is worth more than everything else on both spec sheets combined, because photon output is the quantity plants respond to and it is the one figure you cannot infer from anything else. Lumens cannot be converted into it. Lumens are weighted by the sensitivity of the human eye, which peaks in the green where plants are least responsive and falls away in the deep red where they are most, so the conversion factor depends entirely on a fixture's spectrum — a spectrum Sunco does not publish either. Anyone who quotes you a PPFD for a fixture that publishes only lumens has invented it.

What 48.42 µmol/s actually buys

A board at 2.7 µmol/J delivers rather more than twice the photons per watt. Over a season that difference is paid on the electricity meter every month, and it does not diminish. This is the trade the whole strip-light category asks you to make, and Sunco is the only one in it honest enough to let you see the size of the trade before you commit — which is a real point in its favor, even though the number itself is poor. The full ranking is in most efficient grow lights by µmol/J.

Sizing a shelf with the one number you have

This is the payoff. Because Sunco published a PPF, the 40 W strip can be put through the same arithmetic as a panel costing five times as much, and you can know roughly what you are getting before you order it. Take a standard 4 ft run of shelf, about a foot deep — the shape most seed trays and houseplant collections actually occupy.

104 µmol/m²/s falls in the low band — 50 to 150 µmol/m²/s — on the University of Minnesota Extension's scale. That is enough for a pothos or a snake plant and not enough for a seed tray. The University of New Hampshire Extension puts seedlings at roughly 12 mol/m²/day, and one strip delivers half of that even run 16 hours. This is the arithmetic behind a complaint people make constantly about cheap strips: they bought one, hung it over a tray, and got leggy seedlings anyway.

Two strips per shelf is therefore the configuration to buy, and it is not a guess: it is the published figure doubled and divided by the area you are lighting. No other budget strip in this category lets you reach that conclusion before your money is spent. The general argument for running bars in pairs rather than raising one higher is in bar versus panel coverage.

The 80 W publishes nothing, and we will not fill it in

The obvious thing to do with the 80 W is to carry the 40 W's efficacy across, multiply, and report 96.8 µmol/s. We are not going to, and it is worth saying why, because the arithmetic is tempting and wrong.

Photon efficacy is a property of the diodes, the driver and the optics in a specific fixture. Two models in one product line can share a name and a housing and still use different emitters — and the published figures for these two suggest exactly that, since Sunco lists a CRI for the 40 W and none for the 80 W. A fixture that reports a different set of optical properties is not guaranteed to share the one property that was not reported. Multiplying across models produces a number that looks computed but rests on an assumption nobody has tested. That is a fabricated figure wearing a formula, and this site does not publish those.

So the honest statement about the 80 W is the flat one: its photon output is unknown, it cannot be sized, and it cannot be compared with anything here on output. What it publishes is 80 W, 4000 lumens, a 120-degree beam angle and a 600 W equivalence claim — and equivalence claims are a separate problem, dismantled in watts versus equivalent watts.

What both fixtures cost to run

Note that two 40 W strips and one 80 W strip draw identical power and cost identically to run. The difference is that you know what the pair delivers and you do not know what the single one delivers, and the pair spreads its output along eight feet of emitter rather than four, which is better for uniformity on a shelf.

Sunco against Barrina, which is the real comparison

Nobody cross-shops a SuncoGrow strip against a $150 board. They cross-shop it against the other cheap 4 ft strips, and in practice that means Barrina's T5 bars.

Barrina remains our first pick for a shelf, because 20 W fixtures linkable eight-deep give finer control over how much light lands where, and because the price per linear foot is lower. But Barrina publishes nothing, so buying it means finding out what you got after it arrives. Sunco costs more per photon and links only four-deep, and in exchange it tells you what one fixture emits. Which of those matters more is a genuine judgment call rather than a ranking, and it depends on whether you would rather plan or iterate.

Who should buy which

• Buy two of the 40 W if you want a 4 ft shelf lit to a seedling-adequate level and you want that settled by arithmetic before you order. This is the only recommendation on this page we would make without qualification.
• Buy one of the 40 W only for foliage houseplants — pothos, snake plants, philodendrons — where the low band is the correct target rather than a shortfall.
• Buy the 80 W only if you are comfortable buying unmeasured, the way most of this category is bought. It draws the same power as two 40 W strips and costs the same to run, so the only reason to prefer it is if one fixture suits the space better than two.
• Buy neither if photons per watt is what decides it. At 1.21 µmol/J you are paying roughly twice the running cost of a board for the same light, and over several seasons that gap exceeds the difference in purchase price.

What Sunco does not publish

For the 40 W: no PPFD at any distance, no efficacy figure, no coverage area, no diode manufacturer or LED count, and no fixture dimensions beyond the 4 ft length. For the 80 W: all of that, plus the PPF itself and the CRI. Both fixtures are ETL, FCC and RoHS listed, rated at 50,000 hours, damp rated and carry a three-year warranty, which is a more complete reliability picture than most of this category offers.

The pattern across this site is that fixtures which publish photon data tend to publish it because it is competitive. Sunco published a figure that is not competitive, which is a small act of candor worth noting even while we report that the figure is low.