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We are beginning siman 2, where the Chayei Adam discusses flowerpots. We have learned (s341-342) that a plant inside a flowerpot can still absorb nutrients from the ground. If the flowerpot is touching the ground, affecting that connection is a form of kotzair.
The Chayei Adam writes that one is chayav for kotzair for moving a flowerpot with a hole from the ground and placing it somewhere which breaks its ability to absorb from the ground, such as a rock or a table. The plant is able to extract nutrients from the ground, even when it is not planted directly into the ground, so removing it is a form of kotzair. This applies even if the hole is on the side of the flowerpot. According to Rashi and Tosfos, this removal is kotzair miderabanan, but according to the Rambam, it is assur mideoraysa (see shiurim s341-342).
The Chayei Adam points out that we have already learned that some poskim hold that any vessel made of wood-even without a hole-has the same status, since the wood is a type of plant itself and is able to pull nutrients from the ground. Others hold that any utensil made of earthenware can absorb through its material. Therefore, the Chayei Adam paskens that any utensil made of earthenware or wood which is holding a plant is assur to move due to a safeik deoraysa of kotzair. This applies even if it is on a second floor and not directly on the ground surface. If one detaches something from the plant b’shogeig, they could potentially be chayav a korban.
The Chayei Adam clarifies that the above halachos apply to plants. Regarding trees, some opinions understand that detaching from a tree will always be kotzair, even if the tree is in a pot which does not have a hole. If the pot has dirt in it, or some of the tree sticks out beyond the area of the pot such that it can derive nutrients from the ground, all opinions would agree that it is considered connected to the ground, and detaching from it would be kotzair.
If one removes plants from a pot which does not have dirt in it, and does not have a hole in it, they are patur. We will explain this halacha in the upcoming shiur, be’ezras Hashem.
Summary
It is possible for a plant to absorb nutrients from the ground without directly touching the ground. Therefore, removing a plant which was already absorbing nutrients in such a manner is kotzair.
Similarly, these halachos apply to materials which are porous, such as earthenware and wood.
These halachos apply both to plants and trees. In addition, some hold that detaching from a tree will be kotzair even if the pot it is in does not have a hole.