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Sprout & Spectrum

Where to Buy Grow Lights

The listing you buy from is usually not the page with the specification on it. Here is how to shop this category without losing the numbers.

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

A retail store aisle with lighting products on display

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.

#ProductBest forEfficacyPrice
1
A square white LED grow panel hanging above leafy seedlings indoors
Spider Farmer SF1000
Publishes PPF to two decimal places and an efficacy figure that actually divides out of it. That internal consistency is rarer in this category than it should be.
Full specs on the brand site2.5 umol/J
2
Linked LED strip lights mounted under a wire shelf above trays of seedlings
Barrina T5 4ft Grow Light Strips
The default seed-starting bar for good reasons — 4 ft long, linkable in series, cheap per foot — and the reason we built a coverage calculator, because Barrina publishes no photon data whatsoever.
Widely stockedNot published
3
A screw-in LED grow bulb in a desk lamp aimed at a potted houseplant
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.
Standard socket, easy to find1.82 umol/J (ours)

The reasoning

Before anything else: we earn a commission when you buy through the links on this site, at no cost to you. That is how the site is funded and it is stated on every page that carries a link, at the top, before the first one. The full arrangement is on our affiliate disclosure page. It does not change what we rank or what we say is missing from a spec sheet — three of the nine fixtures we cover publish no photon data at all and we say so on every page they appear on, including the ones we recommend.

The problem with buying from a listing

Retail listings are optimized for conversion, not for specification. The figures that actually let you size a fixture — PPF in µmol/s, efficacy in µmol/J, PPFD with a measurement distance — are usually on the manufacturer’s own product page and frequently absent from the retail listing entirely.

What listings substitute instead is the wattage inflation covered in watts versus equivalent watts: a title claiming 1000W attached to a fixture drawing 100 W. Every figure on this site comes from the manufacturer page for exactly this reason, and each is linked at the bottom of the page it appears on.

Where we sourced every specification on this site
Brand pages

Manufacturer product pages, linked from the sources block on each page — not retail listings. One exception is the GooingTop clip light, which has no manufacturer spec sheet at all, and we flag that wherever it appears.

How the channels differ

What each channel is actually good and bad at
ChannelStrengthsWeaknesses
Large online marketplacesWidest selection, fast returns, most of this category's volumeListing specs are unreliable; near-identical unbranded fixtures are hard to tell apart
Manufacturer directThe full spec sheet, correct model numbers, first-party warrantyFewer models, and the price is rarely better
Home improvement retailersYou can see the fixture; easy in-person returnsNarrow selection, usually bulbs and shop lights rather than horticultural panels
Garden centersAdvice from people who grow thingsVery limited stock, and usually the more expensive end
Hydroponics specialistsThe best product knowledge in the categoryOriented toward tents and commercial scale, not a shelf in a spare room

How to shop this category properly

  1. Find the manufacturer’s product page first. Get the PPF and the efficacy from there. If neither exists, you now know something important about the fixture before you have spent anything.
  2. Size it in the coverage calculator against your actual area, and check the result against your plant’s target.
  3. Then find the model number wherever it is cheapest. A model number is the thing that carries the specification; the retailer does not change it.
  4. Check the return window before you buy. With three of nine fixtures publishing no output data, the returns policy is the only recourse if a light turns out to be inadequate.

Watch for these

  • Unbranded fixtures with no manufacturer page. If there is no brand site with a spec sheet, there is no specification — only a listing. The GooingTop clip light is in this position, and we say so on its page.
  • Model numbers that differ by one character. Brands revise fixtures without renaming them prominently. Match the model exactly to the spec sheet you read.
  • Bundles that inflate the price. A hanging kit and a timer are inexpensive separately; check the bundle is actually saving you something.
  • Wattage in the title. Covered above. It is almost never the draw.

What we do and do not have a stake in

We link to Amazon, and we earn a commission on qualifying purchases. We are not paid by any manufacturer, we have not been given any product, and nobody has paid for a placement or a ranking on this site — there are no sponsored positions to sell. Where we recommend something whose data is missing, we say the data is missing in the same paragraph. That is the whole arrangement, and it is set out in full on the affiliate disclosure and the editorial policy.

Every pick in full

A square white LED grow panel hanging above leafy seedlings indoors
01

Spider Farmer SF1000

LED panel

Full specs on the brand site

Publishes PPF to two decimal places and an efficacy figure that actually divides out of it. That internal consistency is rarer in this category than it should be.

What Spider Farmer publishes

Power draw
100 W +/-5% at 100-277 V AC (source)
PPF (photon output)
249.21 umol/s (source)
Efficacy
2.5 umol/J (source)
Stated coverage
2 x 2 ft core, 3 x 3 ft maximum (source)
Spectrum
650-665 nm, 730-740 nm, 2800-3000 K, 4800-5000 K (source)
Diodes
Bridgelux (source)
Dimming
Yes, dimming knob (source)
Dimensions
32.5 x 29.0 x 5.9 cm (source)
Rated life
55,000 hours (source)

Our arithmetic

  • Does the published efficacy check out against the published PPF?: Yes — 2.49 umol/J computed against 2.5 umol/J published
    249.21 umol/s / 100 W = 2.4921 umol/J. The published 2.5 umol/J is that number rounded. Not every brand's two figures agree like this, which is exactly why we divide them.
  • Average PPFD across its 2 x 2 ft core footprint: about 536 umol/m2/s
    2 ft x 2 ft = 4 sq ft = 0.372 m2. 249.21 / 0.372 = 670 umol/m2/s at perfect uniformity; at a 0.8 uniformity factor, about 536 umol/m2/s.

Who should skip it

Skip it if raw output is what you are buying — the TS 1000 delivers 38% more photons per second, at the cost of 50 W more draw.

Linked LED strip lights mounted under a wire shelf above trays of seedlings
02

Barrina T5 4ft Grow Light Strips

LED bar

Widely stocked

The default seed-starting bar for good reasons — 4 ft long, linkable in series, cheap per foot — and the reason we built a coverage calculator, because Barrina publishes no photon data whatsoever.

What Barrina publishes

Power draw
20 W per fixture; an 8-pack draws 160 W (source)
Spectrum
5000 K (source)
Dimming
No; on/off switch per fixture, linkable up to 8 in series (source)
Dimensions
4 ft strip, 120-degree beam angle, 120 V AC (source)

What Barrina does not publish

  • PPF in umol/s — for any strip in the range
  • PPFD at any stated distance
  • Photon efficacy in umol/J
  • LED count per strip, and rated lifespan

Who should skip it

Skip it if you need to know what you are getting before it arrives. There is no published PPF, no PPFD and no efficacy figure, so nothing about its output can be verified in advance.

A screw-in LED grow bulb in a desk lamp aimed at a potted houseplant
03

SANSI 36W BR30 Grow Light Bulb

Grow bulb

Standard socket, easy to find

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

+Where is the cheapest place to buy grow lights?
It varies by model and by week, which is why we do not publish prices we cannot verify at the moment you load the page. What is consistent is the approach: get the specification from the manufacturer's page, then find that exact model number wherever it is cheapest.
+Should I buy direct from the manufacturer?
For the specification, always read the manufacturer's page. For the purchase, direct is rarely cheaper, though it does guarantee you are getting the model you researched and gives you a first-party warranty.
+Are grow lights from big box stores any good?
The selection is narrow — mostly bulbs and shop lights rather than horticultural panels — and shop lights are specified in lumens, which cannot be converted to photon output. If you want to size a fixture arithmetically, that channel usually will not give you the numbers.
+Do you get paid for these recommendations?
We earn a commission when you buy through our links, at no cost to you, and we disclose that at the top of every page carrying one. No manufacturer pays us, we have received no free products, and no placement on this site is for sale.

Sources

Read next

Where this sits

This page belongs to Fixture Reviews and Roundups. 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.