I live in Michigan and I have brought my plant in for the winter and I need to change the pot it is in because it has grown so much over the summer. I was wondering if what kind of soil would be good to add to make sure it makes it through the winter indoors.
There are many good growing medium formulations for container grown citrus. The basic are: Good/Excellent drainage, pH of approximately 6.5, non compacting, high aeration. Here is the formation that I use with my citrus trees (62 varieties). 4-part Coconut Husk Chips (CHC) to 1-parts peat moss. To this mixture I add slow release Osmacote, STEM (Soluble Trace Element Mix). CHC do not degrade, therefore have a container life of approximately 5-7 years. CHC's do not compact and offer a very high degree of aeration. The natural pH of Coconut Husks is 6.5, which is perfect for citrus. Lastly CHC hold up to 7 times their weight in water, while retaing good aeration and drainage. They make an excellent growing medium. Now for the bad news. In your case your tree is already in a much more compact and dense growing medium. If you repot your tree into a larger container and fill in the bottom and around the edges with CHC's I believe the water would take the path of least resistance and just flow down the side of the container ithrough the more open CHC's and not into your heaver medium. However for any new trees I would HIGHLY recommend CHC's. - Millet
Millet was the first to introduce this a few years back, An folks I will tell you one thing I myself have or has never lost another container tree since. Millet tested this on his own tree's before making it public, If I may add... If we get a tree in a soil mix we gently remove the soil by dunking in water, or a gentle spray to remove the dirt mix taking your time, as to not damage the roots an replacing the mix within the root system an repot as usual as Millet stated above "I would HIGHLY recommend CHC's." I would VERY HIGHLY recommend it. Dale