Short answer: we built it because in Saudi Arabia, water — not land, not light — decides whether a commercial lettuce farm survives. A Riyadh grower came to us with a clear brief: supply hotels, restaurants, and caterers (the HoReCa sector) with consistent lettuce and leafy greens 365 days a year, in one of the most water-stressed climates on earth. Open-field irrigation in that environment loses most of what you apply to evaporation and drainage. So we engineered a recirculating NFT (Nutrient Film Technique) system with 1,300 growing channels and 260 nursery channels, all 3.66 meters of food-grade PVC, fed by rockwool-raised seedlings. This is the full account of that greenhouse project in Saudi Arabia — the specs we shipped, the decisions behind them, and the trade-offs I think every buyer should weigh before copying the design.
TL;DR — 5 Takeaways from This Saudi Greenhouse Project
- The system runs 1,300 growing channels (50 mm holes, 150 mm spacing) plus 260 nursery channels (30 mm holes, 80 mm spacing) — roughly 31,000 growing positions fed by a continuous seedling pipeline.
- Recirculating hydroponics can cut water use by over 90% versus soil farming — the decisive argument in a country where irrigation efficiency sits near 50% against a global average of 85%.
- Every channel is installed with a slight slope, because a moving nutrient film prevents stagnation, keeps roots oxygenated, and evens out nutrient delivery along the full 3.66 m length.
- Rockwool-plus-sponge seedling production exists for one reason: uniform seedlings make the harvest calendar predictable, which is what HoReCa contracts actually pay for.
- The economics now work locally: Saudi Arabia imports close to 80% of its food, but Riyadh-region growers report hydroponic vegetables can already undercut import prices.
Why does a greenhouse project in Saudi Arabia almost force you into hydroponics?
When buyers ask me whether soil or hydroponics is "better," my honest answer is: it depends on your water balance — and in Saudi Arabia the water balance answers for you. The Kingdom relies heavily on non-renewable groundwater aquifers, and its irrigation efficiency is around 50% compared with a global average of 85%, according to the UN Food and Agriculture Organization. Improving that efficiency sits at the heart of Vision 2030's National Water Strategy. In plain terms: every liter you pour onto open soil in Riyadh's heat is a liter you mostly lose.
The market has already voted. Saudi Arabia's indoor farming market was valued at USD 173.3 million in 2025 and is projected to reach USD 301.7 million by 2031 at a 9.7% CAGR — and hydroponics alone accounted for 54% of that revenue (Mordor Intelligence). The same analysis notes the Kingdom directs close to 88% of its freshwater to agriculture while renewable freshwater availability stays below 100 cubic meters per person per year — a level associated with absolute water scarcity. That is why I tell buyers a Saudi greenhouse project is really a water project wearing a greenhouse's clothes: the structure controls climate, but the irrigation philosophy decides whether the farm pencils out.
Hydroponics answers this because recirculating systems reuse their nutrient solution instead of losing it to evaporation, drainage, and runoff — peer-reviewed work puts the water saving at over 90% versus conventional production, with fertilizer use down by up to 60% (Scientific Reports, Nature portfolio). For our Riyadh client, whose customers are hotels and restaurants that cannot accept supply gaps, that closed loop was not an efficiency upgrade. It was the license to operate.
Why NFT channels instead of soil beds, drip lines, or deep water culture?
We evaluated the usual four candidates with the client before committing, and I want to show the reasoning rather than just the conclusion:
- Open soil or substrate beds: rejected immediately — incompatible with the water constraint and with the uniformity HoReCa buyers demand.
- Drip-irrigated substrate: I ruled this out on maintenance math, not ideology — 31,000 plants means tens of thousands of emitters, and in a dusty desert environment emitter clogging is a daily patrol job, not a monthly one. Root-zone moisture also drifts plant to plant, which shows up at packing as inconsistent head weights.
- Deep water culture (rafts): I like rafts for lettuce — but 31,000 positions on rafts works out to roughly a thousand square meters of open water surface under a translucent roof, and every square meter of it is an evaporation and algae-management liability. Rafts also fight staggered harvesting: pulling single heads off a shared raft disturbs the roots of every neighbor, while a channel lets the team clear one position without touching the next.
- NFT channels: chosen — a thin, continuously moving film of nutrient solution that roots sip from, with everything unabsorbed returning to the tank.
The research backs the crop-level choice: in head-to-head lettuce trials, NFT has demonstrated a 6–10% higher yield efficiency than floating raft and Deep Film Technique systems (Scientific Reports). I recommended NFT for this project because it is the only mainstream system where the water loop, the root-zone oxygen, and the harvest logistics all improve at the same time. Rafts win on simplicity; NFT wins on control — and a HoReCa supply contract is fundamentally a control business.
One more practical point from the export desk: NFT channels ship compactly. Fifteen hundred-plus channels of 3.66 m PVC nest efficiently into containers, which kept freight per plant-position low for a Saudi-bound project — a cost line most system comparisons quietly ignore.
Why exactly 1,300 growing channels plus 260 nursery channels?
This is the question I get most from buyers studying the project specification sheet, so let me open up the math. The two channel groups do different jobs:
The 1:5 ratio between nursery and growing channels mirrors the crop calendar: lettuce spends roughly one-fifth of its life in the nursery and four-fifths in the growing channels, so each nursery wave exactly refills the positions freed by each harvest wave. Get this ratio wrong and you either starve the growing channels of transplants or drown the nursery in unsold seedlings. I sized the nursery at 260 channels precisely because under-sizing it is the most common self-inflicted wound I see in commercial lettuce projects.
The hole specs are equally deliberate. Thirty-millimeter holes at 80 mm spacing in the nursery maximize seedling density while root balls are small; fifty-millimeter holes at 150 mm spacing in production give mature heads the airflow and elbow room that prevent tipburn and collapse. The layout mixes horizontal runs with A-frame structures to raise positions per square meter of greenhouse floor without shading the lower tiers.
Why rockwool and sponges for the nursery — and why the channels slope?
Two design details look small on a spec sheet and matter enormously in operation.
We start every seedling in rockwool cubes and growing sponges rather than seeding into channels, because germination is the one stage where moisture and oxygen must be independently controllable — and uniform seedlings are what make a commercial harvest calendar predictable. Restaurants do not order "lettuce, approximately." They order a size, a weight, a look, every delivery. Rockwool's sterile, uniform structure is how you hit that spec week after week. Net pots in 35 mm and 50 mm carry the seedlings from nursery tray to growing channel without transplant shock.
Every horizontal channel in this system is installed with a slight slope rather than perfectly flat, because a moving nutrient film cannot stagnate — and stagnation in a hot climate means depleted oxygen, warming solution, and stressed roots within hours. The slope keeps flow smooth from inlet to outlet along all 3.66 meters, improves oxygen availability at the root mat, and equalizes nutrient delivery so the last plant on the channel grows like the first. It costs nothing extra at installation — you shim the racks once — and it pays back every single day.
The channels themselves are food-grade PVC, free from heavy metals, which matters more in the GCC than elsewhere: sustained high solution temperatures accelerate leaching from inferior plastics, and this farm's entire brand is clean, safe produce for premium food-service buyers.
What were the real trade-offs — the parts case studies usually skip?
I would rather you hear the hard parts from me than discover them after signing. Three trade-offs shaped this project:
First, NFT is pump-dependent in a way rafts are not: the thin film gives you control, but if circulation stops in Riyadh's summer, root-zone temperature climbs fast — so we engineered the plumbing around pump redundancy and reservoir shading, and I now treat backup pumping as non-negotiable scope in every desert NFT quote. The water you save with a closed loop is only safe if the loop never stops.
Second, cooling, not water, became the dominant operating cost line. The greenhouse structure and shading carry the climate load, and buyers should budget energy accordingly — the water savings pay for the system, but they do not pay for August. I say this in every Saudi consultation because it changes the financial model honestly.
Third, uniformity demands discipline: 31,000 growing positions only stay uniform if EC and pH are managed daily, because a recirculating system amplifies small nutrient drifts across every channel at once. The same loop that saves 90% of your water will distribute a mixing error to 31,000 plants in an afternoon. We scoped the project with that operational reality on the table, and the client's team runs it accordingly.
How did a 1,560-channel system get from our factory to a Riyadh greenhouse?
Buyers planning their first GCC project often underestimate the logistics chapter, so here is how we ran it. Because Miilkiia owns its factory with in-house R&D and production, all 1,560 channels — the 1,300 growing channels plus the 260 nursery channels — were drilled, capped, and quality-checked as matched sets before container loading, because hole-spacing consistency across a thousand-plus channels is what guarantees uniform plant spacing on the farm. A drilling tolerance that drifts even a few millimeters compounds across 3.66 meters and shows up later as uneven head sizes.
The full bill of materials traveled as one coordinated shipment: channels, end caps and connectors, net pots in 35 mm and 50 mm, seedling trays, growing sponges, and rockwool. I insist on complete-set delivery for commercial projects because a farm waiting on a missing connector is a nursery wave missed — and in a continuous-production system, one missed wave echoes through five weeks of harvest. Everything was specified for compatibility from seeding to harvest, so the client's team assembled, leveled, sloped, and plumbed the racks against our layout drawings with remote installation guidance.
Commissioning followed the sequence I now recommend everywhere: water-run the loop first and check flow on every channel, then transplant a single nursery wave and watch it for a full week, and only then ramp to full staggered production. The temptation is always to fill all 31,000 positions immediately; the discipline is to let the system prove itself on one wave first. That week of patience is the cheapest insurance in the whole project.
What happened after commissioning?
The farm went into continuous production supplying restaurants, catering services, and food businesses across its HoReCa network. From actual operation, the system delivers uniform growth across all channels, consistent leaf size, color, and texture, clean root development, and stable output suitable for commercial supply. The crop list covers butterhead, Batavia, Lollo Rosso, Lollo Bionda, Endive, and Crystal lettuces, plus kale, arugula, basil, and Swiss chard. The customer's own summary was short and, for an export manager, perfect: "the system is running well."
The market context makes this more than one farm's story. Saudi Arabia imports close to 80% of its food, yet Riyadh-region growers now report that with current shipping costs, locally grown hydroponic vegetables can undercut import prices — one AlKharj project, also in the Riyadh region, announced capacity for 6,000 lettuce heads a day (Hortidaily). I built this system the way I did because the Saudi lettuce question has flipped: it is no longer "can you grow it here," it is "how fast can you scale before your competitor does."
Interactive: Estimate Your Own NFT Channel Count
Planning a lettuce project? Enter your weekly harvest target and crop cycle length; the estimator applies this project's actual geometry (~24 plants per 3.66 m growing channel at 150 mm spacing, nursery at 1/5 of growing capacity). No JavaScript? Use the reference table below.
Frequently asked questions about this Saudi NFT lettuce project
Why do greenhouse projects in Saudi Arabia usually choose hydroponics over soil?
Because water is the binding constraint. Saudi Arabia relies heavily on non-renewable groundwater and its irrigation efficiency is around 50 percent against a global average of 85 percent, according to the FAO. Recirculating hydroponic systems can cut water consumption by over 90 percent versus conventional soil farming, which turns a water problem into an engineering problem that can actually be solved.
How many lettuce plants does a 1,300-channel NFT system hold?
With 3.66-meter channels drilled at 150 mm hole spacing, each growing channel holds about 24 plants, so 1,300 channels give roughly 31,000 growing positions. Staggered transplanting from the 260-channel nursery keeps those positions continuously occupied for year-round harvest.
Why are NFT channels installed with a slope instead of flat?
A slight slope keeps the nutrient film moving so it cannot stagnate, improves oxygen availability at the root zone, and evens out nutrient distribution along the full 3.66-meter channel. In a hot climate, stagnant solution warms up fast and stresses roots within hours.
Why use rockwool and sponges for seedlings instead of seeding directly into channels?
Rockwool gives controllable moisture and root oxygen during germination, which produces uniform seedlings. Uniform seedlings are what make a commercial harvest calendar predictable — essential when restaurants and caterers expect the same size and quality every delivery.
Is locally grown hydroponic lettuce competitive with imports in Saudi Arabia?
Increasingly yes. Saudi Arabia imports close to 80 percent of its food, but growers in the Riyadh region now report that with current shipping costs, local hydroponic production can undercut import prices — one AlKharj project alone announced capacity for 6,000 lettuce heads per day.
What is the biggest operational risk of an NFT lettuce system in a desert climate?
Heat and pump dependence. The thin nutrient film heats quickly and roots suffocate if flow stops, so the system needs shaded or cooled reservoirs, disciplined EC and pH management, and redundant circulation pumps sized so a single failure never leaves channels dry.
Final take
If I compress this whole greenhouse project in Saudi Arabia into one sentence, it is this: the 1,300 channels were never the point — the point was a water loop, a seedling pipeline, and a harvest calendar disciplined enough to keep a HoReCa contract in a desert. Every spec on that sheet, from the 150 mm spacing to the sloped racks to the redundant pumps, exists to protect one of those three things. Copy the specs if they fit your climate and your buyers; more importantly, copy the reasoning.
Evaluating a hydroponic lettuce or leafy-greens project in Saudi Arabia or the wider GCC? Send me your target crop, weekly volume, and site location — I will come back with a channel configuration, nursery ratio, and a containerized delivery plan built on the same logic as this Riyadh farm. The full project specification is published here: Customized Hydroponic Channel System for a Commercial Lettuce Farm in Saudi Arabia.