If you are starting with leafy greens such as lettuce, basil, pak choi or palak, you will mostly be choosing between two systems: NFT (nutrient film technique) and DWC (deep water culture, also called raft). Both work. The right choice depends less on which is "better" and more on where you are building, how reliable your power is, and what you want to grow.
This article compares them in plain terms so you can decide with confidence.
How each system works
NFT: a thin film of nutrient solution flows through slightly sloped channels, usually food-grade PVC. Plants sit in net cups along the channel, and their roots hang into the flowing film. The solution drains back to a tank and is pumped round again.
DWC: plants sit in net cups on floating rafts, usually foam or thermocol sheets, on a bed of nutrient solution about 15 to 30 cm deep. An air pump and air stones keep the water oxygenated. Roots are always in water.
Weight: the question that decides rooftops
This is the biggest practical difference.
- NFT is light. Very little water sits in the channels at any time, so a multi-tier unit is manageable on many rooftops.
- DWC is very heavy. A bed with 20 cm of water weighs about 200 kg per square metre before you add the bed itself. Never put a raft system on a roof without a structural check by a qualified engineer.
If you are on a terrace in a city flat or an older building, NFT is usually the safer choice. If you are at ground level in a net house or polyhouse, weight is not a problem and DWC becomes an option.
Power cuts and pump failures
- NFT depends fully on the pump. If the pump or power fails on a hot day, roots can dry out and plants can start to wilt within roughly 30 to 60 minutes. You need a reliable backup such as an inverter or battery, plus a spare pump.
- DWC is far more forgiving. The large volume of water keeps roots wet for hours, and the water temperature changes slowly. A short power cut does not usually kill the crop, although the air pump still matters for oxygen.
If your area has frequent outages and you cannot afford a backup, this is a strong argument for DWC at ground level.
Water temperature and summer
Indian summers are hard on hydroponics. Warm water holds less oxygen and encourages root disease.
- In NFT, the thin film warms quickly under the sun. Shade nets, shaded tanks and sometimes white or insulated channels help.
- In DWC, the deep water changes temperature slowly, which is a real advantage. But once it gets too warm, the whole bed is at risk.
In both systems, keep the nutrient tank in shade and aim for water below about 25 to 28 °C for lettuce. Beyond that, expect problems unless you can cool the water.
Water and nutrient use
NFT uses less water and nutrient per plant because the system holds a small volume. DWC needs a lot to fill the beds, and a disease such as pythium can spread across a whole bed quickly. With NFT, a problem in one channel is easier to isolate, although the shared tank still connects them.
Plants per square foot
NFT can be built as an A-frame or in several tiers, so you can grow more plants in the same footprint. DWC beds are usually single level, so plants per square foot are lower unless you build stacked beds, which adds weight and complexity.
Cost: roughly similar, but watch the details
General cost ranges for a 500-plant leafy greens unit are in the range of ₹1 lakh to ₹2.8 lakh for NFT including a structure and backup, and in the same broad range for DWC, though the beds, liners and ground preparation cost differently. DWC can look cheaper on the channel line, but you may need a stronger floor or base, extra tank volume and more nutrient to fill the beds. Compare complete quotes, not single items. For a detailed breakdown, read how much a small hydroponic leafy greens setup costs in India.
Which crops suit which system?
- NFT: lettuce, herbs, pak choi, palak. Short crops with compact roots.
- DWC: lettuce and basil do very well, and many growers like it for fast, uniform lettuce.
- Neither is ideal for large fruiting crops such as tomato and cucumber. Those usually go into Dutch buckets or similar systems.
Dutch buckets are sometimes suggested to beginners, but for leafy greens they are a poor fit. You get only a few plants per bucket, media and labour per plant are high, and the crop lives for only four to six weeks.
Skill level and daily work
Both systems are beginner-friendly if you keep to a routine. DWC has fewer moving parts, which makes it simpler to run. NFT needs more attention to channel slope, flow rate and blockages from long root mats, but harvesting is easier at working height. In India NFT is the most common system for small commercial units, so spare parts and local help are easier to find.
A simple way to decide
Answer these four questions:
- Where will it sit? On a roof, choose NFT. On the ground, either works.
- How reliable is your power? If it is poor and you cannot afford a backup, lean towards DWC at ground level. If you can arrange backup, NFT is fine.
- What do you want to grow? Mostly lettuce and basil: both work. A wider mix of herbs and greens, with plans to scale in tiers: NFT.
- How much space do you have? Limited space favours NFT because of its multi-tier layout.
If you are still unsure, start small, with a single NFT channel or a single raft, and run it for two or three cycles before you scale. A small pilot costs little and teaches you more than any article.
The bottom line
For most beginners in India, especially on rooftops, NFT is the practical first choice: light, compact, widely available and easy to scale, as long as you invest in a pump backup and shade. DWC suits ground-level setups and areas with unreliable power, thanks to its large, stable water volume. Choose based on your site, your power and your crop, not on what looks best online.
This article is general information, not engineering or financial advice. Have any structure checked by a qualified engineer. See the Disclaimer.