Thought I'd share here for those starting out, or for those interested, the repot of a 3.5 ft fukushu kumquat grown indoors year round. I believe this tree was 2-3 years old when I got it and fruiting at the time. It's a grafted tree. It is now 6 years old and outgrew the pot last year. As I was unable to find a new pot (I needed the full size 14 inch pot that matched it's "twin" a Nagami kumquat that lives on the other side of tbe window). I refreshed the soil and waited until this year to repot the tree. I believe that due to stress from being rootbound the tree didn't fruit last year.
I have these big trees on steel rolling drip trays rated for 500lbs, so to get the tree outside to the repotting area I simply rolled it to the door then lifted it and carried it the 4ft to the edge of my repotting space. I use a cheap painters drop cloth and weigh it down with the soil bags and rocks so that cleanup will be easy, and I can keep pests from outside mostly out of the tree while I repot. The tree was fairly rootbound so it came out of the pot easily. You can see the root mass in the photo below. I had already pulled some of the roots loose before thinking to take a photo.
I should note that I grow in 100% organic soil made from bark, forest products, pumice, sand, some various fertilizers (chicken, bat, feather meal), and both dolomite and oyster shell limes. I use this soil because it is what I might make myself if I had the space to store soil, and it works well as a free draining soil. I also only use organic citrus fertilizers innoculated with mycorrhizae to help break it down in containers.
Here is the plant after I worked some of the old soil from the roots. You can see how big the root system is on this tree. (This is a huge contrast to my Nagami, which came from a local greenhouse and had no end to problems. It's root system was probably a quarter the size). It was very healthy. I do use a root rake meant for bonsai trees to loosen the roots and work the soil loose.
Final photo is the tree in its new pot and back in its growing space. I do replace most of the old growing media and plant into new soil every repot. But I also go 3-5 years between repots if I can afford to do so. Since the pot was slightly oversized for the tree I didn't fill it all the way and left two inches at the top. This also helps with watering indoors and minimizes spills.
I thought this might also be a good place to share some tips/tricks on repotting to be a resource for new growers, so feel free to share some of your own.
New Fukushu Kumquat has Rootstock sprout?
Kumquat Fukushu: to bare root & repot in 5.1.1 or not so late?
fukushu kumquat grafted 6-22-2021
Fukushu kumquat grafted to flying dragon 8-28-2020
Travis in PHX (9b)