Is it necessary to replace old soil when repotting a rootbound plant?

Question

Yesterday, I repotted a rootbound monstera into a larger pot. I had been told that replacing the old soil wasn't a high priority if it meant cutting out too many roots, so I simply added new soil around the old soil along with coconut coir and fertilizer pellets.

But now I am wondering if it's necessary to more aggressively detangle the roots and get rid of the old soil (~1.5 years old). I read on a website that as much as a third of the roots could be cut away from the bottom, and almost all the old soil removed.

Picture of my plant

• How much old soil is okay to keep around when repotting?
• How aggressively do you cut at the roots of a rootbound plant?
• Should I remove the monstera and redo the repotting procedure?

Thank you so much! :)

Answer 1

No, leave it alone, it's fine. It is not critical to root prune, and certainly not critical to remove the soil which forms the existing rootball. All that's critical is to use proper, new potting soil to pack round the rootball in a clean, larger pot with drainage holes and water in well, then look after it ongoing.

Generally, the only time you might try to remove soil is if its infected or infested with something and you need to get rid of it before repotting.