Autopot Systems Explained: How They Work and Which to Buy
Autopot systems water your plants without pumps, timers or electricity. Each pot feeds itself from a shared tank, so you can leave a room for days. This guide covers how they work, which size to buy, what to grow in, and how to set one up.
How Autopot works
The tank sits slightly above pot height and feeds the pots by gravity, so the system is silent and has no pump to fail. Under each pot is a tray with its own AQUAvalve. The valve fills the tray to 20 mm, then closes and stays shut until the tray is completely empty, then fills it again.
That gives every plant a dry spell between waterings, and because each pot has its own valve, each plant drinks at its own pace - a thirsty plant fills more often than a small one next to it. Most other automatic systems water every plant on the same timer.
Which system?
| System | Tank | Area it suits |
|---|---|---|
| 1-Pot | 47 L | One specimen or mother plant; the tank lasts even a demanding plant well over 10 days. Add-on modules make it 2 or 3 pots |
| 4-Pot | 47 L | About 1 m2 - a 1 m tent. Lasts 4 big fruiting plants 3-5 days, much longer earlier on |
| 8-Pot | 100 L | 2-3 m2: a 2 x 1 m area; 2.4 x 1.2 m tents suit the XL version |
| 12-Pot | 225 L | 3-4 m2 |
| 24-Pot | 400 L FlexiTank | 6-10 m2 |
| 36-Pot | 400 L FlexiTank | 9-15 m2 |
| 48-Pot | 400 L FlexiTank | 12-18 m2 |
Which pots?
- Standard: 15 L square plastic pots.
- XL: 25 L square-to-round pots, for bigger plants - see the XL systems.
- FlexiPot: breathable fabric pots of 20, 35 or 50 L, which air-prune the roots.
The 24-, 36- and 48-pot systems come with Iceline supply pipe, which keeps the feed cooler on its way from the tank to the plants.
What to grow in
For the plastic-pot Autopot systems we recommend a good soil such as Plagron Light Mix or Canna Terra Professional Plus, always on a 40-50 mm bed of clay pebbles in the bottom of the pot. Soil copes with the widest range of pH, and it's the medium we've found works reliably with feeding from below. We advise against coco on its own in these pots unless it's mixed with soil. Our potting soil guide compares the soils we sell.
The FlexiPot product pages say the fabric pots work with soil, coco or hydro media. If you're unsure, ask us before you buy.
Setting up
- Put the tank slightly above pot height and keep the AQUAvalves level and clean.
- Fill the pots and hand-water from the top for the first 7-10 days, so the roots get established.
- Then mix your feed in the tank and turn the tap on. From now on the valves do the watering.
- Top the tank up when it gets down to about a quarter full: it is gravity fed, so it needs some weight of water to run well.
- Clean the filter in the tank every few weeks, and keep organic or thick, syrupy additives out of the reservoir - they can block the valves.
For which feed, and how much each week, see our Canna Terra feed chart or the Biobizz feed chart (dose it in the tank, not as a thick additive).
Spares and other Autopot kit
- Autopot accessories and AQUAvalves: AQUAvalves, 6 and 9 mm filters, inline taps, top hat grommets, silicon inserts and the 47 L tank.
- FlexiPot parts, Flexi-Tube by the metre and the barbed reducing cross for extending a system.
- Tray2Grow: the same AQUAvalve under a tray with capillary matting, for seed trays, microherbs or the Tray2Grow Planter.
- AQUAbox Straight: waters a row up to 1.2 m long in a raised bed or border, and can run from a water butt.
Pipe and fitting sizes
Flexi-Tube is sized by its outside diameter (OD), and each size needs fittings made for that size. The Autopot filters and top hat grommets come in 6 and 9 mm; the 8- to 48-pot Standard and XL system pages name a 16 mm filter, and the Inline Filter Low Pressure is a barbed 16 mm filter that its page says goes straight after the tank. If you are not sure which suits your system, ask us.
| Pipe | What it is for |
|---|---|
| Flexi-Tube 6mm (OD) | Black tube for older Autopot systems (pre-2021) with black AQUAvalves |
| Autopot Flexi-Tube 9mm (OD) | Blue tube for the latest AQUAvalve5 |
| Flexi-Tube 16mm (OD) | Supply line on larger (5+ pot) Autopot systems; standard IWS Flood & Drain |
| Flexi-Tube 25mm (OD) | Mainly IWS PRO - see our flood and drain guide |
| LDPE Pipe, 13 mm | Drip lines; sized by the inside, so it fits 16 mm OD fittings |
On a 16 mm supply line, the Autopot Barbed Reducing Cross gives two outlets and a reducing tee from the Barbed T-Pieces gives one; both come in 16/16 > 6mm and 16/16 > 9mm versions, so pick the one that matches your pot tube. End the line with the 16 mm size of our End Stops, or with one of the Inline Taps if you want to flush it through.
Watch the tap sizes: the Inline Taps page says its 4, 6 and 13 mm taps fit 6, 9 and 16 mm OD pipe, so a 16 mm supply line takes the 13 mm tap. The Autopot accessories page lists its own 6mm and 9mm Inline Taps; ask us which one fits your tube. To run drip lines to pots without an AQUAvalve, see our dripper systems guide.
Quick answers
Do Autopots need electricity?
No. They run on gravity alone: no pumps, timers or power.
How often do I fill the tank?
It depends on the size of the plants. The 4-pot system's 47 L tank lasts four big fruiting plants 3-5 days, and much longer while they are small. Top up at about a quarter full.
Can I use coco?
Not on its own in the plastic Autopot pots - mix it with soil. The FlexiPot pages say their fabric pots take coco.
Which size tube does my Autopot take?
Systems from before 2021, with black AQUAvalves, take the black 6 mm tube. Systems with the latest AQUAvalve5 take the blue 9 mm tube. Larger systems (5+ pots) also run a 16 mm supply line from the tank. Not sure which you have? Measure the outside of your old tube, or ask us.
More Growers' Guides
Not sure what you need? Call the shop on 0117 971 3000 or pop in to the Bristol store and we'll help you pick.