In parshas Vayakhel your Parsha sheet quote ” Rav Nissim Kareltiz (Chut Shani 10:4) permits spitting outside, or walking on plants with wet clothes or hair (from a sudden downpour) because nobody waters in this manner, and he has no intention of watering plants”
But some Poskim say spitting outside is Zoreh; I think Rav Menashe Iliya (a daas yachid) says even spitting inside is Zoreh.
You are addressing the plowing/planting melacha, but do you think Zoreh is a problem here?
Thank you for your question.
Although I am not the person who wrote the article, but I looked it up, and indeed R’ Nissin Karelitz zt”l was actually talking about zoreah. He says that that it is permitted to spit a small amount on plants. This is because this is a minute amount of liquid, and even if it would cause some growth it would not be noticeable, coupled with the fact that this not the normal way that a person waters plants. (Additionally, the person has no intention to water the plant.) This is also why it is not an issue if a little bit of water drips from a person’s hair. It is a minimal amount and the person has no intention to water the ground and it is not the usual manner of doing so.
It is possible that there are other opinions, this is the opinion that was quoted by the author.
איו איסור לירוק קצת בשבת ע”ג קרקע או ע”ג זרעים כיון שאין הדרך להשקות זרעים ע”י רוק, ואין לחשוש בקצת רוק משום הצמחת הזרעים.