Almost every complaint we get about size comes from the same place: a pot is measured across its top opening, and a plant is sold by the nursery bag it is currently in. An 8 inch pot is not the pot for an 8 inch plant — it is the pot for a plant currently in a 6 or 7 inch bag.
The one-size-up rule
Move a plant into a container one to two inches wider than the bag it came in. More than that and the soil holds water the roots cannot reach, which on a balcony means a permanently wet pot and, eventually, root rot.
- Nursery bag 4 inch → pot 5 to 6 inch
- Nursery bag 6 inch → pot 8 inch
- Nursery bag 8 inch → pot 10 inch
- Anything above 12 inch: think about whether you can still lift it once it is full and wet.
Depth matters more than width for some plants
Herbs, succulents and most flowering annuals are shallow-rooted and do fine in a wide, low pot. Chillies, tomatoes and any climbing vegetable want depth. A 10 inch shallow bowl and a 10 inch deep cylinder hold very different amounts of soil, and the listing gives both numbers for exactly that reason.
What we check before we list a pot
Every container on this site is listed with the top diameter and whether it has a drainage hole and a saucer. Where a carton does not state the depth, the listing says so instead of estimating — we would rather leave a number out than print one we cannot stand behind.