IWS Flood & Drain Pots and Outers (16 Litres) — Modular Hydroponics Components for Active Growing
Best for: Intermediate growers building or expanding a flood and drain hydroponics system where precision and proven yields matter
Our thoughts
This is proper hydro kit from a manufacturer that's been doing this since 1976. The 16L size sits perfectly in the middle of the range — big enough to get real results, small enough to scale up without committing the earth. If you're moving beyond beginner systems and want a flood drain setup that actually delivers, IWS is the one growers pick.
The IWS Flood & Drain Pots and Outers (16 Litres) are component pots designed as part of Nutriculture's modular flood and drain hydroponics system. Each unit consists of an outer pot (which connects to your system's pipework) and an inner pot (which holds your substrate). When the system floods, nutrient solution rises from underneath to saturate the root zone, then drains back completely — cycling oxygen through the media and driving nutrient uptake. This is active hydroponics that works, and 16 litres is the sweet spot for growers who want serious yields without overcomplicating things.
How it compares
The IWS flood and drain system competes in the serious active hydroponics space.
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vs Wilma (drip irrigation) — Wilma feeds from the top down; IWS floods from the bottom up. IWS delivers more oxygen cycling and stronger root development, though Wilma is easier for absolute beginners
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vs AutoPot (passive system) — AutoPot needs no electricity and is simpler to run, but grower feedback consistently shows IWS outperforms for yield and precision. Professional growers pick IWS every time
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vs RAIN/Alien flood systems — Both are flood and drain, but IWS operates at zero pressure, uses less electricity, and offers unlimited layout flexibility
In short: if yield and control matter more than simplicity, IWS is the choice.
Usage guidance
The 16L pots work as part of a complete IWS system (6, 12, 18, 24, 36, or 48-pot configurations available).
Substrate options
The inner pot accepts clay pebbles, coco coir, or a 60/40 clay/coco blend. If you're running coco, the sealed inner pot design prevents fragments blocking your system pipework.
System assembly
Each outer pot connects via glands and fittings to your central pump and timer. The IWS Universal Pot Stand is essential — it positions your pots so the flood level hits exactly right and has built-in V-shaped drainage to return nutrient back to the reservoir.
Flood timing
Set your timer in 1-minute increments. This precision is where IWS shines — you dial in your flood cycle (typically 15-30 minutes, 2-4 times daily depending on media type and ambient conditions) and let it run consistently. Consistency is the whole game with flood and drain.
The oxygen advantage
When the solution drains, fresh air fills the root zone. When it floods, stale air gets pushed out. This constant cycling prevents root rot, locks in oxygen, and drives growth. It's why professional growers see better yields with flood drain than passive systems.
Technical specifications
- Inner pot capacity: 16 litres of substrate
- Outer pot dimensions: 280mm (height) x 280mm (diameter)
- Material: Durable plastic construction
- Compatible substrates: Clay pebbles, coco coir, or 60/40 clay/coco blend
- System integration: Connects to IWS pipework via glands and fittings; part of modular 6, 12, 18, 24, 36, or 48-pot systems
- Essential accessory: IWS Universal Pot Stand (provides correct flood level and drainage)
- Manufacturer: Nutriculture (IWS — Intelligent Watering Systems)
Who this is for
- Intermediate to advanced growers ready to move beyond beginner passive systems
- Growers prioritising yield and precision control over simplicity
- Semi-commercial or professional operations running 12-36 plants where consistency matters
- Operators scaling up — starting with 12 pots and expanding later without replacing core infrastructure
- Anyone who's grown with Wilma or AutoPot and wants to see what a proper active system can do
- Growers in tighter spaces who need to maximise output from limited footprint
Our take
This is proper flood and drain kit from a manufacturer with 25+ years of proven form. The 16L size gives you enough substrate volume to get real results without the scale commitment of larger pots. Professional growers don't pick IWS by accident — they pick it because it outperforms everything else on yield, and the modular design means you can start small and expand as you go.
If you're building a serious growing setup and want a system that's repeatable, controllable down to the minute, and genuinely delivers the goods, this is worth picking up while stock lasts. Does exactly what it should, day in, day out.
