Fabric, Air-Pot or Plastic Pots? How to Choose (and What Size)
A pot is more than a container: its shape and walls change how fast the growing medium dries out and how the roots grow. This guide compares Air-Pots, fabric pots and plain plastic pots, and helps you pick the size.
The three kinds
| Pot | How it works | Watch out for |
|---|---|---|
| Air-Pots | Holes in the wall air-prune the root tips, so roots branch instead of circling the pot | Dry out faster than standard pots, especially if you hand water |
| Fabric pots | Porous fabric drains well, airs the root zone and air-prunes the roots; folds flat, with handles | Dry out faster too; need a saucer or tray |
| Plastic pots | Solid walls with drainage holes; the cheapest and easiest to keep watered | Roots can circle the wall; easier to overwater |
Air-pruning is the big idea behind Air-Pots and fabric pots: when a root tip reaches the air at the wall it stops, and the plant grows more fine feeder roots instead. RootMASS fabric pots can also go in recirculating systems, where the fabric acts as a filter between the medium and the reservoir.
Air-Pot sizes
| Size | Diameter x height | Use |
|---|---|---|
| 1 L | 10 x 14.5 cm | Rooted seedlings and cuttings, before potting on |
| 3 L | 15 x 23.5 cm | Intensive hydro and coco systems, plants up to 60 cm |
| 5 L | – | Medium-sized plants |
| 9 L | 23 x 30 cm | The most popular size in soil; mother plants up to 100 cm |
| 12.5 L | – | Larger plants |
| 20 L | 31 x 31.5 cm | Very large plants up to 200 cm, outdoors or as long-term mother pots |
| 38 L | – | Big plants that need a lot of room |
Fabric and plastic sizes
- RootMASS fabric pots: 1, 2, 3.8, 12, 16, 20, 25, 30 and 39 litres.
- Round plastic pots: 10 L (28.3 x 22 cm), 15 L (31.8 x 26 cm), 20 L (35.8 x 29 cm), 25 L (35.8 x 33 cm) and 30 L with handles.
- 11 L square pots: 25 cm square by 26 cm high - square pots fit closer together in a tent.
- Square-to-round pots: 1, 2, 3 and 5.5 L, for taking cuttings and seedlings through to their final pot.
- For hydroponic systems: heavy-duty net pots (80, 140 and 200 mm) and mesh propagation pots.
Which should I choose?
- Hand watering in soil: plastic or 9 L Air-Pots. Plastic stays wet longer, which is easier to manage; Air-Pots grow a better root ball but need watering more often.
- Coco on drippers: Air-Pots or fabric pots - coco likes frequent feeds and lots of air, and the faster drying stops it from staying soggy. See our coco guide.
- Automatic watering: the Autopot FlexiPot puts a fabric pot on an Autopot tray. See the Autopot guide.
- Cuttings and seedlings: 1 L Air-Pots or small square-to-round pots, then pot on. See propagators and cuttings.
Quick answers
Do Air-Pots need watering more often?
Yes. The holes that air-prune the roots also let the medium dry faster, so expect to water more often than in a plastic pot of the same size.
Can I reuse fabric pots?
Yes - empty, wash and dry them. They fold flat for storage.
What goes under fabric and Air-Pots?
A saucer or tray to catch run-off: see our trays and saucers.
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.