Dubai imports most of its food and has almost no farmland of its own — and summer temperatures regularly climb past 43°C. On paper, that makes it one of the hardest places on earth to grow food. Yet Dubai is now home to some of the biggest indoor farms in the world, including Bustanica, widely described as the world's largest vertical farm.The reason these farms work isn't luck — it's that the air inside them is controlled down to the last detail: temperature, humidity, light, water, and nutrients. Of all of these, humidity is one of the trickiest and most expensive to get right. This article explains, in plain terms, what it actually takes to control humidity and climate inside a commercial indoor farm in Dubai.
Why Dubai Makes This Harder Than Normal
Growing plants indoors always means managing the air around them. But doing it in Dubai comes with a twist most other countries don't deal with:
It's brutally hot outside. Cooling the building is usually the single biggest expense in running an indoor farm here, simply because the outdoor heat never really lets up.
The air outside is dry, but the air inside isn't. This is the part people don't expect. Dubai's outdoor air is often quite dry. But once you seal plants inside a growing room, they release moisture constantly through a natural process called transpiration — basically, plants "breathe out" water vapor. Add irrigation and hydroponic systems on top of that, and the air inside a grow room can get humid fast, even in the middle of the desert. So the real job isn't "drying out a humid country" — it's controlling a humid little world sealed inside a dry one.
Water is precious. Since fresh water is scarce in the region, many facilities try to capture and reuse the water that condenses out of the air during cooling and dehumidification, instead of letting it go to waste. Bustanica, for example, recycles a large share of its water this way.
The Equipment That Actually Does the Work
1. Dehumidifiers — the core piece of the puzzleRemoving excess moisture from the air is the single most important job in a grow room. Get it wrong, and you invite mold, mildew, and plant disease. Get it right, and plants grow faster and healthier.Different parts of a farm need different types of dehumidifiers:For the growing area itself, purpose-built grow room dehumidifiers are designed specifically to stop mold and keep air moving evenly around the plants.In a large facility, humidity usually isn't controlled room by room — it's tied into the building's air system through ducted dehumidifiers, so every room stays consistent.Bigger operations that run non-stop need heavy-duty dehumidifiers built for continuous, industrial-scale use.If a farm also has cold storage or a cooler propagation area next to the main growing space, cold room dehumidifiers stop condensation and frost from building up where temperatures shift.In some rooms — especially cooler or very tightly controlled ones — standard dehumidifiers just can't keep up. That's where desiccant dehumidifiers come in, since they work well even where regular units struggle.
2. Humidifiers — yes, sometimes you need to ADD moistureThis surprises people, but it's true: sometimes the air gets too dry, especially right after seeds are planted or when air conditioning strips too much moisture out of a room. Young seedlings need a humid environment to survive, so humidifiers are used to add moisture back in during those early, delicate stages.
3. Heat recovery — saving the energy you already paid forGrow rooms constantly need fresh air brought in and stale air pushed out. The problem is, every bit of air leaving the building takes the energy you spent cooling or dehumidifying it right along with it. Heat exchangers (HRV systems) capture a large chunk of that energy before it escapes, instead of just throwing it away. For a farm running 24/7, this can make a real dent in the electricity bill.
4. Air purifiers — protecting against mold and diseaseHumid, enclosed spaces are a perfect breeding ground for mold spores and airborne germs, which can quietly wreck an entire crop. Air purification systems filter this risk out of the air, and some of the most advanced facilities in the region also use physical dividers between growing zones so that if one area does have a problem, it doesn't spread to the rest of the farm.
5. Sensors and automation — the brain of the systemNone of this equipment works well running on its own. The better facilities connect their dehumidifiers, air conditioning, and sensors into one system that automatically adjusts itself as conditions change — instead of relying on someone to walk around and check gauges by hand.
Humidity Needs Change as Plants Grow
Plants don't want the same humidity level their whole life. As a general rule of thumb in controlled growing:
Just planted / seedlings: high humidity (roughly 70–80%) so young plants don't dry out
Growing phase: medium humidity (roughly 55–65%)
Flowering / fruiting phase: lower humidity (roughly 40–50%) to reduce the risk of mold and improve quality
These are general guidelines used in controlled-environment growing, not a fixed rule — the right numbers can shift depending on the crop.
Why This Matters So Much for the Bottom Line
Across the board, the people running these farms say the same thing: energy costs from cooling and humidity control are the biggest pressure on profits — bigger than labor, bigger than competing with imported produce. In other words, the climate control system isn't just "equipment in the background." It's close to the heart of whether the farm makes money or not. A farm with a well-thought-out, properly matched set of equipment has a real cost advantage over one running mismatched machines that fight each other.
What to Think About If You're Setting One Up
If you're planning or upgrading an indoor farm in Dubai, here's what actually matters:
Work out how much moisture your specific rooms will produce, based on plant size and stage — don't just guess with a generic rule
Control temperature and humidity together, not as two separate settings
Choose dehumidifiers sized to run continuously, not just handle occasional spikes
Build energy (heat) recovery into the design from day one, not as an afterthought
Plan to capture and reuse water where possible
Treat each zone differently — seedlings, growing plants, and flowering plants each need their own settings
This is exactly the kind of planning humidity.ae helps commercial clients work through — looking at the site, calculating the actual load, and building a system around the specific crop and layout, instead of selling a one-size-fits-all package. If you're planning a new facility or think your current system might be undersized, get in touch for a site assessment.
1. Isn't Dubai too dry for humidity to even be a problem?
That's the part. No. The outdoor air being dry doesn't matter once you seal plants inside a growing room. The plants themselves plus the irrigation system create humidity on the inside. The room can get humid even in the middle of the desert.
2. Do all growing rooms need the humidity level?
No. Young seedlings need humidity plants in their growing phase need a medium amount and plants that are flowering or fruiting need less. A good system adjusts as the plants move through these stages of using one fixed setting for everything.
3. Why does cooling cost much for indoor farms here?
Because the building is constantly fighting temperatures that can climb past 43°C for months at a time. Cooling and humidity control together usually end up being the ongoing expense for a farm, bigger than staffing.
4. Does recycling water actually make a difference?
For farms yes. Capturing the water that condenses out of the air during cooling and dehumidification then reusing it can meaningfully cut down on how fresh water the farm needs to buy. Which matters a lot in a region where water is scarce and costly.
5.How do I know if my current climate control setup is undersized?
Common warning signs include humidity swinging outside the range condensation forming on walls or equipment mold appearing anywhere, in the facility or energy bills that keep climbing without a clear reason. A proper site assessment can calculate what your rooms actually need and compare that against what your current equipment can deliver. Humidity.ae offers this as a starting point.
6. Why is cooling so expensive for indoor farms here?
Because the building is fighting outdoor heat that can sit above 43°C for months on end. Cooling and humidity control together are usually the single biggest ongoing cost for a farm — bigger than staffing, in most cases.
7.What does a heat exchanger actually do, and why bother with one?
It recovers energy that would otherwise just vanish every time stale air gets pushed out and fresh air comes in. Instead of paying to cool or dry that incoming air completely from scratch, the system reuses energy you already spent — which chips away at the electricity bill over time.
