I now have two tuberous cactus in 4 inch diameter pots which are 4 inches high. I want to got to a tall square plant pot and I need to know what size I need that is one size bigger than the round plant pots I am using now. I understand there is a difference in size between the round and square pots, is this so?

This is for Daisyl go into the following website and you will see tuberous cactus (which I have and they are copiapoa's) www.kadagarden.com/potting.html

to NGA

Can you show us some photos? I'm not sure what a tuberous cactus is. Generally, cactus require pots that are wider than they are tall as all the roots are on the surface.

Sorry Daisyl that web site should have read:

www.kadasgarden.com/pottinghtml

The link still isn't working.

Hi Stan

Knowing your cactus are Copiapoa will help. I am going to assume they are both round, solitary cactus. I have never heard them refered to as turberous cactus before.

Try this link:

http://kadasgarden.com/Cpottin...

The difference between a round pot and a square pot is that a square pot is a round pot with corners. So a square 4-inch diameter pot will have more volume (64 cu. in.) than a round 4-inch diameter pot (50.2 cu. in.).

As you are putting two round cacti into one square pot, the diagonal of the new pot needs to be big enough to accommodate both of them. Maybe you should look for a shallow rectangular pot.

Daisy