Removing the old soil off the root ball during repotting may damage fragile roots. But it is not going to kill your plant.
In fact, there are situations when it is necessary to do so, especially when repotting succulents and for switching seedlings to a hydroponic system.
In this article, we will go through the situations when you should remove the soil off the root ball and how you can do so safely.
1. When you should remove old soil from roots
You should remove the dirt from the roots:
- when the plant was previously in contact with a plant that was infected with bacteria, fungi or bugs.
- When you have just received the plant from someone else or from the store, which often uses peat as the growing medium which is hydrophobic and compact when left to dry.
- When you are changing the type of growing media, for example from soil to a gritty mix.
- when you are repotting into a small new pot with no much room for new potting medium. This is especially the case for succulents as they prefer to fit in small pots with little soil to hold too much moisture.
- When the old soil has become water-repellant or hydrophobic and compacted. This is true especially for succulents as the frequent dry outs between watering often turn their soil into hydrophobic.
- When you are repotting the seedling to a hydroponic system.
2. When you should not remove soil from roots
In most cases, it is not necessary to remove all the old soil from the root ball and you should not do so, especially:
- when the old soil is not bad,
- when the old soil is of a similar type as the new soil,
- when the roots of the plant are fine and delicate,
- when the plant is very root-bound, e.g. 90% roots, 10% soil.
- when the potting medium is firmly attached to the roots, usually inorganic medium such as perlite, pumice.
3. How to remove soil from roots?
If you have to remove soil from the roots of your plant, these three tips may help you do so safely:
3.1 Let soil dry before repot
Time the repot to around the time you think the soil is dry, although not bone dry. Dry soil is easier to manipulate, especially in unpotting and pulling the whole root ball out of the pot and in removing dry soil attached to the roots.
3.2 Loosen root ball from pot
Squeeze the pot to loosen up the root ball and lift the plant out of the pot.
If the pot is hard and is not squeezable, run a garden spatula around the sides of the pot for easy plant removal.
3.3 Break open root ball
To break open a root ball, especially one that is pot bound, you can use your fingers or a sharp object such as a screwdriver, a chopstick, a toothpick, etc. to poke into the root ball. You can also massage the root ball, gently tap it or shake it off.
If the soil is dry, the majority of the soil should come off easily.
If the soil particles are rather coarse, such as pumice, it is enough to remove the soil by just shaking it off.
If the roots are too tangled up or pot-bound, you can use tweezers to carefully tease out the roots.
3.4 Washing roots
Washing roots with water is an effective way to remove soil off fragile roots in compacted soil, which is difficult to break open by fingers.
To do so, swish the plant roots around in a bucket of water. Some people prefer to use the sprayer with strong water pressure instead.
Since succulents prefer dry roots, let the drenched roots dry in room temperature. How long you should dry the roots depends on how susceptible the succulent is to infection and diseases. Let it cool and dry longer, or up to two days, for fragile species.
4. How much soil should you remove from roots?
If you are switching your plant from soil to hydroponics, you should remove all the soil. Otherwise, breaking up the root ball and removing some of the old soil until the tendrils are visible and are not tangled up would be enough.
Don’t force it if small pieces of soil and the roots are all tangled up. It is natural that clumps of soil are attached to the roots. You do not need to scrub the roots clean as long as there are no big clumps of soil left.
5. What to do if roots are damaged during repot?
If you damage the roots during repotting, let the plant dry in the open air for 1-2 days before potting it up in new media as their fresh wounds would become vulnerable to rot and infections.
If you are worried about a potential infection, you can rinse the roots in 1 quart of water mixed with 1 tbsp. of hydrogen peroxide.
In any case, you should not worry about losing some of the fine roots as it will not kill the plant, as long as you do not damage or trim any of the thick main roots.
Removing the soil from the root ball is necessary, especially for repotting succulents that were in bad soil and for switching to hydroponics. To do so, you should let the soil dry a few days before repot, loosen the root ball and remove it from the pot, break open the root ball and wash the roots, if necessary.
In case some of the roots are damaged during repotting, it may stunt the plant a little but it will recover.