The short answer
If you're evaluating a greenhouse lighting supplier right now, the five things that actually decide whether the relationship works are: engineering and spectral support, compliance documentation, warranty follow-through, restock speed, and OEM/private-label maturity. Price per watt comes after all five. Not before.
I've been on the distribution side of horticultural lighting for eight years. I run sourcing and expediting for a grow light distributor that serves greenhouse operations across North America and Western Europe. In my role coordinating rush orders for commercial growers, I've handled somewhere north of 200 emergency jobs — most of them from greenhouse managers who realized about three weeks before a crop cycle that their lighting plan had a hole in it.
The orders that went wrong almost never went wrong on price. They went wrong on documentation, lead times, or a spec that looked clean on the PO and turned out to be something else entirely at install. Speed, quality, paperwork. Pick all three, in that order.
That pattern is why the checklist above is the checklist. And it's why, when a supplier's opening line is "our price per watt is…," I brace for an hour that wastes both our afternoons.
Why the price-first conversation loses
In February 2023, we placed a rush order with a low-cost supplier we hadn't used before. A mid-size greenhouse client needed 240 units in 19 days to hit a transplant window. Normal lead time is 6–8 weeks. We found a vendor with inventory stateside, paid about $3,800 extra in air freight (on top of a base cost that was already 30% under our usual supplier), and delivered on day 17.
The client's alternative was pushing the transplant by three weeks. At their scale, that was a lot more than $3,800 of lost schedule.
The units arrived. Two of them had driver issues within the first ten days. That's a normal-ish failure rate for a first batch, and honestly the 2/240 doesn't bother me. What bothered me was that the warranty response took eleven days to even acknowledge. The client had a lighting row running at partial capacity the entire time. That's where the math gets ugly.
I don't have hard data on industry-wide first-batch defect rates, but based on our own order log — which I've been keeping since 2019 — my sense is that quality issues affect somewhere in the 8–12% range of first deliveries, loosely defined. The bigger issue isn't the defect itself. It's what happens next.
Evaluating a greenhouse lighting supplier: the five criteria
1. Engineering and spectral support
Ask a specific question: "Can you give me a DLI calculation for my crop, my greenhouse transmittance, my latitude, and my canopy geometry?"
A supplier that sends back an actual document — not a spec sheet with marketing on it — is a different kind of supplier. When I'm triaging a rush order and I call a vendor with that question, I can usually predict within five minutes whether they'll be useful six months from now.
Brands that come up in this conversation repeatedly include Heliospectra — you'll see "heliospectra grow light" and "heliospectra horticultural lighting" queried a lot by growers who are already asking the right questions about DLI and spectral matching. That's not a coincidence. The queries follow the operators who take this seriously.
2. Compliance documentation
This is where a lot of otherwise-fine distributors get caught out. You do not want to discover at customs that a certificate doesn't apply to the specific SKU on the pallet. I learned that one the expensive way.
What to actually ask for: UL or ETL listing documents under that specific product family, EU CE Declaration of Conformity, RoHS statements, and — where relevant to the project — DLC qualification for North American efficiency rebate programs. Ask for dated PDFs. Not a marketing page that says "certified."
3. Warranty follow-through
Every supplier says "five-year warranty." Almost none will tell you how they handle claims that have already happened. Ask: what percentage of warranty claims over the last twelve months were denied, and on what basis? "We don't track that" is an answer. It's just not the answer you wanted.
4. Restock speed
This is the actual emergency angle. Your greenhouse doesn't lose one fixture. It loses a row. If a supplier's restock cycle is 14 weeks, they're not a horticultural lighting supplier for production operations — they're a project supplier. Those are two different things, and mixing them up costs real money.
5. OEM and private-label maturity
If you're a distributor looking to put your own label on a platform, the questions that separate a real OEM relationship from a brochure are: who owns the tooling, what are the MOQ tiers, how is the label and packaging customization handled, and — this one gets missed — how does firmware or control integration work if the underlying product iterates. Get it in writing before the first PO.
The decision that kept me up
I went back and forth for two weeks between a cheaper new supplier and our established one on a 400-unit order. The new supplier offered 24% savings; the established one had a documented 3-day restock guarantee and a warranty history I could actually verify with two other distributors. On paper, the new supplier made sense. My gut said no.
I went with the established one. That decision cost us roughly $4,100 in margin on the deal. The client hit their cycle. Nothing broke. Everything was boring. Which, for a greenhouse, is the whole point.
Looking back, I should have run the cheaper option on a small pilot first, before putting it into the main consideration set. At the time, I didn't have a pilot protocol — we added one in Q1 2024. Now any new supplier gets a 20-unit test run before they're allowed into a real order.
What I still can't answer
I don't have reliable long-term data on LED degradation rates across different greenhouse environments. The L90/L70 projections suppliers give you are conditioned numbers — controlled temperature, controlled humidity, controlled drive current. A real greenhouse in the Netherlands in July is not a controlled environment. I wish I had tracked returned-unit performance more carefully in the first four years; what I can say anecdotally is that units we ran at lower drive current consistently outlasted the higher-output ones, which isn't a surprise but is worth more than most spec sheets.
I also don't know what the right answer is for growers running hybrid setups — partial LED retrofit over an existing HPS install. The math there depends on so many site-specific variables that I'd distrust anyone handing me a general rule.
When price should be first
Two situations.
One: you're running a scoped trial — one bay, one short cycle, low stakes if it doesn't work out. Cheapest usable option is fine. Stress the word usable; get the compliance and spec right, then optimize price.
Two: you already have a validated platform and you're reordering a known SKU from a third factory. That's closer to commodity sourcing and price weight goes way up. But only after the documentation, lead time, and warranty history have passed.
Otherwise? The head of the industry has gotten very competitive on OEM and private-label programs. The price gap between a good supplier and a cheap one has narrowed a lot since 2022. What hasn't narrowed is the service gap.
What I'd actually do next
Build a shortlist. Send the whole list the same set of seven questions. Don't ask them to fill in a form — just ask. Watch response time. Watch how well the answers actually map to the question. Watch who answers a different question than the one you asked.
Then take the two or three most grounded responders and ask for one reference call with an existing distributor or grower. Twenty minutes each.
That whole process takes two days. It'll save you more than it costs.
