Square or round.

Yes lots there to look at.
Just doing the Maths if I could find a a 12in square pot it would contain 0.2 cubic ft more compost than a round one, and take up the same space.
Bigger they get the more space you get for roots.

 

Many commercial growers will use the cheap square pots at the early stages but then plant on to a more sturdy round pot before it goes to a retailer. Cost comes in to play, the small 7cm and 9cm square pots are the cheapest, but very flimsy and split when the plant starts to get pot bound. The more sturdy Aeroplas square pots are more expensive than the equivalent sturdy Aeroplas round pot. A 5L Aeroplas square pot is 120% dearer than a 5L Aeroplas round pot, to a commercial grower. It is the same with the large outdoor planters, round is cheaper than square.

Hydroponic stores tend to sell sturdy square pots up to 25L in size.

Square Plant Pots - Durable Plastic & Drain Holes - 0.5L-25L (londongrow.com)

 

Yes, I'm kind of thinking maybe as you go up in size a round pot is stronger than a square one.

 

For pot displays round is best in my opinion , I find them easier to plant up and they seem to flow better and look more natural .

For little pots 7-9cm I use square until I run out of them, they fit better in trays and the propagator , I always make square holes when planting in the garden as well.

 

I prefer square to round, unfortunately round are more common. I have some that have a round top and morph into a square base.
The other thing is while I can easily get 10, 15, 20 L round pots I've not seen square ones of a similar size.

 

My problem is I cant get my head around litres for pot sizes.
Just dont register how big it is.

 

The Aeroplas ones do the opposite, square at the top and round at the base.



Hydroponic suppliers are your best bet for larger square sturdy pots, but they tend to only go up 25L which tends to fit with the growing tray systems they sell.

 

I am a fan of square pots for sowing and growing on upto about 2 litre pots, and use elixir garden supplies too as mentioned by Bobtg above. However, beyond this (5 ltr+) I use round pots, no idea why, but I prefer the look of round at this stage. My Pots I refill each year with summer bedding etc are all round. That said, my biggest pots that house permanent plants are all square. So I am no help really

 

I should say I seldom buy plant pots, except with plants in them, they then get used until given away with a different plant or they split. So more round than square pots and these are in the standard plant sizes sold by nurseries. Upshot is I often really want to use a different size to the ones I can find.

 

I'm the same, The only pots I ever buy empty are large ones for final/permanent or semi-permanent planting, and occasionally one for a houseplant. All the ones I use for growing - on are ones that came with plants in, 35 years' worth of them so I have a vast range of sizes and shapes, round, square and "morphing" ones which are a pain to stack when not in use - they need their own stack.