Pot size is the volume of growing medium available to one plant, usually given in litres or US gallons (1 US gal = 3.785 L). Across many crops, plant biomass rises with rooting volume: a meta-analysis found that doubling pot volume increased plant size by roughly 43% on average.
In practice
Common indoor sizes are 11-25 L (3-7 gal) for photoperiods and 11-15 L (3-4 gal) for autoflowers. Larger pots buffer water and nutrients, so they forgive missed waterings. Smaller pots dry faster, which allows more frequent feeding and tighter control.
Myth check
House position: bigger pots give bigger yields, within reason, but root volume is not the whole story. It is a trade-off against feeding frequency. The founder has grown more than 4 oz (113 g) dry from a 16 oz (about 0.5 L) cup by pushing water and nutrients hard with high-frequency fertigation. A small pot fed many times a day can match a big pot watered every few days; a small pot watered like a big one will starve. See drain-to-waste and crop steering.
Don't confuse with
- Root-bound: a symptom of a pot being too small for the watering regime, not a fixed property of pot size.
