The Grow Light Specification Checklist I Run Before Every Wholesale Order

Who This Checklist Is For

If you're placing bulk orders for grow lights — whether you're a distributor, a wholesaler, or sourcing through a greenhouse lighting supplier for your own operation — this checklist is for you. Seven steps. If you already have samples in hand, it takes about 45 minutes to run through. If you don't, add a week.

I started putting this together after a five-figure screw-up in 2019. I did what most first-timers do: compared the wattage numbers on a bunch of supplier listings, picked the one that looked like the best deal, and ordered 400 units in one shot. About 60 of those were a Hortilux grow lamp model I'd searched for by name. The rest came from a supplier I can't even remember now. Turned out the wattage numbers weren't measuring the same thing. By March, I was dealing with burnt ballasts at six months and a stack of customer calls I'd rather forget.

So the list below isn't theory. It's the thing I now do before every deposit goes out the door.

Step 1: Pin Down What "Wattage" Actually Means

"1000W equivalent" and "430W actual draw" are not the same number, and the gap between them is where budgets go to die. For HPS lamps — which is what a Hortilux grow lamp traditionally is — the number is usually real. For LEDs, the "equivalent" figure can be inflated two or three times over.

Before you compare anything, ask one question: what's the actual input wattage, and under what test conditions? If the spec sheet only shows an equivalent number, stop there.

Checkpoint: ask for a reference meter reading, or buy a $30 plug-in watt meter and test three units yourself. If the numbers are off by more than 5%, walk. I assumed the corner-cutting would show up in build quality and not the core spec. Didn't verify. Turned out the spec sheet was the first thing they fudged.

Step 2: Break Down the Spectrum — Don't Accept "Full Spectrum"

"Full spectrum" means nothing. You need three numbers, and they don't cover the same thing:

• PPF — photosynthetic photon flux, in µmol/s. Total photons the fixture emits.
• PPE — photosynthetic photon efficacy, in µmol/J. PPF divided by wattage. This is the efficiency number that actually matters.
• PPFD — photosynthetic photon flux density, in µmol/m²/s, measured at a specific distance. If a supplier says "PPFD 2000" without telling you the distance, that number is worth zero.

Also ask for the spectral distribution chart. A "full spectrum" tuned for a greenhouse is a different animal from a generic white LED, and if the supplier can't send a chart, they probably don't know either.

Step 3: Get Certification Documents Before You Sign

DLC listing, UL, ETL, CE if you're exporting — these tell you the fixture was independently tested. Not "yes, we meet the standard" in an email. Actual certificate numbers, issuing bodies, and valid dates.

Certificates expire. I've seen a full container sit at customs because the DLC certificate for the driver had lapsed three weeks earlier and nobody on the supplier side caught it. It was eventually released, but that shipment missed its season.

Checkpoint: verify at least one certificate number directly with the issuing body before you wire money. It takes ten minutes.

Step 4: Confirm Fixture and Ballast Compatibility

This is the step most people skip — including me, until I learned not to. If you stock fixtures and lamps separately, or if you're replenishing one SKU while keeping another in rotation, make sure the new batch mates with what you already have. And the other way around.

We once had a batch of 180 units come in with a socket orientation shifted about 3 millimeters from the previous shipment. Three millimeters. That's a $900 loss plus a customer explanation I'd rather not repeat. The supplier genuinely didn't think it mattered.

Checkpoint: pull 10 random units from the new batch and mate them against your existing stock before you sign off on the bulk order.

Step 5: Calculate Landed Cost, Not Unit Price

Unit price is maybe 60% of what you'll actually pay. Total landed cost = unit price + freight + duties + customs brokerage + inbound handling + expected breakage + warranty reserve. Ask for that number at every tier.

To put it plainly: a $42 lamp that costs $12 in freight and duty is not cheaper than a $51 lamp with freight included. Vendors who hide fees and add them later rarely come out ahead in the end. After roughly three years and a couple hundred orders, I've come to believe that the supplier who answers "what's NOT included?" before you ask is the one worth keeping.

Frame it as: "Give me the number that lands this in my warehouse." Watch what happens to their response time.

Step 6: Put OEM and Private Label Terms in Writing

If you run your own brand or work with a grow light OEM supplier, these terms need to be on paper:

• MOQ per SKU and per color or size variant
• Tooling or setup fees — one-time or per order?
• Sample fees and re-sample fees
• Whose name goes on the label (this affects warranty liability)
• Who owns the design file or packaging artwork you paid to develop
• Regional exclusivity — yes or no, and for how long

If they won't give you regional exclusivity, your "custom OEM" order is basically a sticker on a fixture anyone else can buy. That's sometimes fine. It just shouldn't be priced like exclusivity.

Step 7: Order Samples — But Not the Sample They Offer

Every supplier sends their A-game unit for sampling. Order three, from different production batches if possible. Run them at full power for at least 72 hours continuous. Measure PPFD hot, not just at turn-on. If the greenhouse or tent is available, put one in it and measure at the actual canopy distance.

Log the batch numbers. If the batch number on your sample doesn't match what shows up in the bulk shipment, you want to have that on record.

Common Mistakes That Keep Showing Up

• Verbal spec confirmations. If it's not in the order confirmation or the contract, it doesn't exist. I've learned to accept nothing as final until it's in writing — not emails, not phone calls.
• Trusting "same as last time." Wiring, drivers, and firmware change between runs. Request the spec sheet fresh every order, every time.
• One certificate, no date check. Certifications have expiry dates. Verify.
• Buying before testing. Even the cheapest watt meter is worth the one-time purchase if you're ordering in volume.
• Skipping the landed-cost math. The lowest unit price is more often than not the highest total cost.

The whole list takes about 45 minutes to run if you have samples. It takes about 45 hours to fix if you don't. I've done the math on that one three times, and I'd rather not make it four.