Just as one may not break off a branch or leaf from a plant growing in soil, so too one may not break off anything from a potted plant. If the flowerpot has holes in the bottom, it is considered connected to the ground. Thus one who plucks anything from it transgresses Kotzer by Torah law. If the flower pot does not have holes in the bottom, it is not considered connected to the ground, as this is not the way plants normally grow. Thus one who plucks anything from it transgresses only rabbinically (SA 336:7; MB ad loc. 42). Similarly, one may not water potted plants (MB 336:41; see n. 4 above).
One may not move a potted plant from its place on Shabbat, because it is muktzeh. It is considered a kli she-melakhto le-isur (see ch. 23) since watering its contents or picking them is prohibited. However, one may move it if he needs the space it occupies (below 23:8). If the potted plant is frequently moved from place to place for aesthetic reasons or so that it can be smelled, it is not muktzeh, since its primary use is a permissible one.
Sometimes moving a potted plant is prohibited on account of Zore’a or Kotzer. For example, if the flowerpot has a hole in the bottom the size of a small root and it is resting on the ground, the hole allows the plant to draw sustenance from the ground, and thus it is considered connected to the ground. Thus, one may not move the pot from the ground and place it on a hard plastic surface, because that would violate Kotzer. Conversely, if the plant is on a hard plastic saucer, it may not be moved from there and placed on the ground, because that would violate Zore’a. Thus, if one needs to move the flower pot to use the space it is occupying, he must be careful to move it together with the saucer underneath it.
If a flower pot tipped over and some of its dirt spilled out, one may not put the dirt back in the pot, because doing so helps the plant grow and thus transgresses both Ĥoresh and Zore’a. Additionally, soil is muktzeh and may not be moved. Even if no dirt spilled, but the flowerpot’s fall exposed the roots of the plant and they will be covered back up if the plant is restored to a standing state, one may not do so even using one’s foot (such that muktzeh is not an issue), because covering the roots violates both Ĥoresh and Zore’a. (One may open a window in a room containing a plant, as explained above at the end of section 3.)
. This law is explained in SA 336:7-8. If a flower pot has a hole in the bottom, one may not lift it from the ground and place it on pegs. Even if it is only removed for a short period of time, and even if there is no object coming between it and the ground, it has nevertheless been distanced from its life source. Similarly, one may not remove the flower pot from the pegs and return it to the ground (SA 336:8 and MB ad loc.)There are many opinions about how big the hole must be. The standard ruling is about 2-2.5 cm. There is disagreement whether floor tiles are viewed as separating the hole from the ground. Brit Olam and Menuĥat Ahava 2:4:7 maintain that they do. R. Shlomo Zalman Auerbach says that floor tiles only separate the hole from the ground when they are on the second floor or higher. Ĥazon Ish maintains that ceramic tiles do not separate, but marble tiles do. If a flower pot is on a plastic saucer, it is equivalent to a flower pot that does not have holes. (See Orĥot Shabbat 18:18 and Harĥavot.) Thus, as long as the flower pot has a saucer underneath it, it may be moved from place to place.