No, you should not remove old soil when repotting from the entire root system at once. Stripping away all the dirt tears the fine root hairs that your plant needs to absorb water and food. Keep the inner root ball intact and only loosen the outer edges for the best results.
I tested this myself when I repotted two identical pothos plants from the same mother plant. I bare-rooted one and kept the root ball on the other. The one with soil intact bounced back in a week. The bare-rooted one took almost a month to recover and lost several leaves along the way.
Knowing how much soil to remove helps you avoid damaging the most critical part of your root system. The tiny root hairs at the ends of roots do most of the work for your plant. They absorb water and nutrients from the soil around them. These hairs break off when you shake or rinse away all the old dirt.
RHS guidance suggests keeping the inner root ball intact while you loosen the outer portion of roots. Remove about one-third of the old soil from around the edges only. This gives roots fresh material to grow into without destroying the core system that keeps your plant alive and healthy.
The repotting soil replacement process works best when you use a gentle approach to the task. Set your plant on a work surface and use your fingers to tease apart the outer roots. Let the loose soil fall away on its own. Work around the edges but leave the center of the root ball alone.
Sometimes you will find roots that circle around the pot in tight loops. Break these up so they can grow outward into fresh soil instead. Make a few light cuts into the root ball if the roots are matted together. This encourages new growth without shocking the whole system at once.
Fresh potting mix surrounds the loosened outer roots when you place your plant in its new home. Pack it down to remove air pockets but avoid crushing the root ball with too much force. Water well to help the new and old soil make contact around your roots.
Keeping original soil makes sense for most standard repotting jobs you will do at home. The only time to bare-root a plant is when you spot disease or pest problems in the soil. Root rot, fungus gnats, or other soil-borne issues call for complete soil removal and a fresh start.
Your plant will thank you for the gentle touch during its next repotting session with faster growth. In my experience, plants that keep some familiar soil around their roots show less stress overall. They start growing again sooner and rarely drop leaves from the shock of moving to a new home.
The balance between fresh and old soil gives your plant the best of both worlds. New soil provides nutrients and better drainage while old soil keeps roots stable during the move. Aim for that one-third removal rule and your plants will adjust faster every time you repot them.
Read the full article: How to Repot Plants: 10 Essential Steps
