You should look at the root system of a plant before making the decision to repot. Many wait too long, while others are too eager to move their plants up. Is the root system as wide as the pot rim or the canopy of your plant? The latter would never be used as an indicator.

Unless you use a very coarse textured medium, be very cautious about potting up. Under employed potting soil can become stagnant, slow to drain. That is not likely to occur with a very porous, chunky mix.

How do I look at the roots? Do i need to pull it out of the pot and potentially put it right back in?

Yep! It's easy to slide a plant out of a container....unless of course, there are few roots and it all crumbles everywhere when you remove the container.

Slide the plant out gently, quickly evaluate the condition of the root mass, then slide it back in until a better time for transplanting. It seems to me that people are hesitant to inspect the roots of plants and there is NO reason for this fear.

The nursery industry relies on the practice of transplanting. When I had my nursery, we transplanted many thousands of woody plants at least twice a year. The practice should be nothing but beneficial as long as the potting medium is an excellent one, and the roots aren't left to sit outside of the container.

We haven't even discussed the benefits of rootpruning! :-o

Rhizo, such a good question, one I never thought to ask and one I have always wondered..

You have given such great advice and I thank you for that!:-)

Hi, my friend. It IS a good question, isn't it? With practice, we can make a pretty good guess about when we should repot, but the only sure method is to check the roots.

Now, if a plant is maturing and you don't want to keep moving it up to a larger sized pot, root pruning will enable you to maintain it in the same container for a long time.

You do that with some of yours, don't you, Mike?

Personally.....I dont even need to take a plant out of a pot....not just citrus but any plant.......I drill extra drainage holes in my pot in the first place and that has included terracotta(masonery bits/be careful....3mm then 5mm then 7mm) as well as plastic......typically 5 or 6mm holes.....with my citrus i put some onion bag mesh at the bottom to stop mix coming out.(cut to size)
All you have to do is lift the pot above your head or tip it on its side carefully and look for signs of roots coming out the holes.....then its time to repot.
If you are really slack and go away and they are rootbound...plants will often try to push themselves up and out of the pot as well but the lift and look/tip on its side is all i ever do. if you pick a container that is 3 to 4 inches bigger all around than the rootball....that will eliminate stagnant water sitting in the pot....i killed a lot of citrus using too big a pot! water just sat there going off.Some plastic pots have some big drainage holes on their sides.....they are good for spotting the roots.