How Does an AutoPot Gravity-Fed Watering System Work?
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An AutoPot gravity-fed watering system waters your plants automatically with no pump, no electricity and no timer. Water sits in a reservoir positioned above your pots, and a mechanical float valve called the AQUAvalve opens under gravity pressure to let a measured amount of water and nutrient solution into each pot. Once the plant has used that water and the soil dries out enough, the valve opens again and repeats the cycle. It is entirely plant-driven: thirsty plants get watered sooner, slower-growing plants get watered less often, and you never have to set a schedule.
This is the same basic idea behind sub-irrigation and float-valve watering that has been used in greenhouses for decades, packaged by AutoPot into a simple modular kit that any UK grower can set up on a shelf or a raised stand. Below is exactly how the mechanism works, what you need to build one, and where it fits against other feeding methods.
How Does the AQUAvalve Actually Control the Water?
The AQUAvalve sits inside each pot and connects back to the reservoir by a length of flexible pipe. According to AutoPot's own technical documentation, the valve "opens to supply water to a 20mm depth and then closes." That 20mm layer sits at the base of the pot, and the growing medium wicks moisture upward from it. As the plant draws water out of the medium and the reservoir of water in the pot base drops, gravity pressure from the header tank pushes the valve open again, topping the pot back up to that same 20mm depth.
No pump, mains water pressure or electricity is involved at any point. The only thing driving the system is gravity, which is why the header tank has to sit higher than the pots. AutoPot's current AQUAvalve5 uses a 5mm inlet, around 66% larger than the previous version, so it delivers water faster and copes better with thicker nutrient mixes without clogging.
What Do You Actually Need to Set One Up?
A working gravity-fed setup has four parts, and DiscountHydro stocks all of them individually so you can build a fresh system or expand one you already own.
- Pots fitted with a gravity-fed valve, sold as a complete 1Pot System kit in sizes from 1 pot up to 36 pots.
- A header tank or water butt, raised above the pots on a shelf, stand or step, holding your water and liquid feed.
- Pipe and connectors linking the tank to each pot's valve, easy to extend as you add more pots to the line.
- A root control disc or root pouch, which stops roots circling round and blocking the valve as the plant matures.
Fill the tank, connect the pipework, and the system runs itself until the tank runs dry. Most growers top the tank up every few days to a week depending on how many pots are running and how thirsty the plants are.
How Many Pots Can You Run, and What Does It Cost?
The 1Pot System is sold in fixed pot-count kits, and buying the version with a reservoir included is the simplest way to start if you do not already own a tank. Here is how the sizes compare:
| Kit size | Price (with reservoir) | Roughly suited to |
|---|---|---|
| 1 Pot | £49.99 | A single large plant, or a windowsill test run |
| 2 Pot | £78.99 | A small shelf or two large plants |
| 4 Pot | £109.99 | A 2x2 tent or a small greenhouse bench |
| 6 Pot | £178.99 | A 3x3 tent or a row of pots along a wall |
| 8 Pot | £278.99 | A 4x4 tent or a full greenhouse bay |
Every pot in every kit size is the same 15 litre size, so the only thing changing between kits is how many plants you can water at once. Larger kits (9, 12, 16, 24 and 36 pot) are also available for anyone scaling up a commercial or large hobby setup.
What You Need for a Complete Gravity-Fed Kit
1Pot Systems (15L Pots) With Reservoir, 4 Pot, £109.99
The complete, ready-to-run kit: four 15 litre pots fitted with AQUAvalves, plus the reservoir tank, all the pipework and fittings you need. The right starting point if this is your first gravity-fed system and you want to water four plants from one tank.
Mega Pot Module, With Root Pouch, 22L, £37.00
A larger 22 litre gravity-fed pot module built around its own wide-inlet valve, with tapered walls and a fabric root pouch insert that prunes roots as they reach the edge. A good option for expanding a system with bigger pots for bigger plants.
Flexitank Water Butt, 225L, £72.99
A collapsible, freestanding header tank with a tap fitted at the bottom, foldable flat for storage when not in use. A practical reservoir upgrade once you are running more than a couple of pots and want a bigger buffer between top-ups.
Gravity-Fed vs Drip Feeding: Which Is Right for You?
A gravity-fed AQUAvalve system and a drip system both automate watering, but they solve the problem differently. A drip system uses a pump and usually a timer to push measured doses of nutrient solution to each plant on a fixed schedule, which gives you tighter control over exactly when and how much each plant receives. A gravity-fed system hands that decision to the plant itself: water is delivered on demand as the medium dries out, with no pump and no electricity to run or fail.
If you want precise, schedule-based dosing and are happy running a pump, our guide to hydroponic drip systems covers that approach in detail. If you would rather set up once and let the system respond to the plant, gravity-fed is the simpler and cheaper route, and it keeps running through a power cut.
What Goes Wrong, and How Do You Avoid It?
The most common AQUAvalve problem is a valve that sticks open or closed because roots have grown into it. Fitting a root control disc from day one largely prevents this. The second most common issue is algae growing inside clear or degraded pipe, which is why AutoPot's pipe is deliberately opaque blue rather than clear. Finally, the header tank has to be raised properly, at least level with or above the height that gets water flowing reliably to every pot on the line, so check your shelf or stand height before you fill the tank for the first time.
Frequently Asked Questions
Do I need electricity to run an AutoPot system?
No. The entire point of a gravity-fed system is that it runs on gravity pressure alone, with no pump, mains water pressure or electricity required.
How often do I need to top up the tank?
It depends on the number of pots, the size of the plants and the tank size, but most growers top up every few days to once a week. A larger tank such as a 225 litre Flexitank Water Butt stretches the interval between top-ups.
Can I mix liquid nutrients straight into the tank?
Yes, that is exactly how the system is designed to be fed. The AQUAvalve5's wider inlet was specifically introduced to cope better with thicker nutrient mixes without clogging.
What size pots does the 1Pot System use?
Every kit size uses the same 15 litre pots, whether you buy the 1 pot starter kit or the 36 pot commercial-scale version.
Do I need a root control disc?
It is not compulsory, but it is a cheap way to stop roots circling into the AQUAvalve and blocking it, which extends the time between system clean-outs.
Can I expand a system I already own?
Yes. If you already have a tank, the 1Pot Systems (15L Pots) Without Reservoir kits let you add more pots to your existing setup without buying another tank.
Ready to Set One Up?
Browse the full range of automatic watering kits, tanks, pipework and spares in our Auto Feeding Systems collection, and build a gravity-fed setup sized to your space.