It’s probably just one of those silly semantics things, but in my mind there is a difference between potting up a plant, and potting a plant on.
To me, potting up something is stealing it from its rightful home, grabbing some soil and a pot, and giving a plant new boundaries. YOUR boundaries, to be exact. You wouldn’t pot up a plant unless you were a greedy plant loving person like myself, and you pot up things like snippets of rooted lovelies from your neighbor’s yard, or adorable Japanese maple babies that have shown up all over a perennial bed, or hunks of Siberian iris that a friend is trying to eighty-six. Stuff like that.
Potting on is different. That’s when an already potted plant has run out of real estate and needs another, bigger pot. You may notice it because of the size of the plant, but what should really be a big hint is that you can’t seem to water it enough. That is because roots are taking up more room than the soil that keeps the roots moist, and squeezing the space in the pot so that the soil that is there becomes compacted . Not a good sitch.
What to do? Just like in my video, remove the plant, ruffle up the crowded roots to encourage them to reach out to the far corners of their new home, and supply the additional space and soil to make them comfy.
So pay attention to your growing charges. The growth rate may surprise you: I remember being caught unaware that people really could have feet large enough to require higher than a size 12, and my poor 14 year old son had to plead for a shopping trip because of my ignorance. The lad’s feet needed to be potted on several times to a final 13 and a half. Surprised the heck out of me!