I had a meat knife (not used for meat within last 24 hours) that was then used to cut vegetables (including hot chili pepper) to make a Parve soup in a parve pot which I was hoping to eventually use for dairy.
Is this new pot now a meat pot? How about the spoon used to stir the soup? (also parve but hoping to be able to covert it to dairy)
Thank you for your question. Even though taste can usually be transferred from a vessel into food only via heat (for example cooking food in a meat pot transfers the meat taste to the food), there is a famous exception. That is when cutting "sharp" (spicy) foods with a knife. In such a case the knife transfers its taste into the "sharp" food. There is an argument as to whether it can also transfer old tastes from the knife (those which are more than 24 hours old, that is not "ben yomo"). Generally Ashkenazim are strict on this issue, with Sephardim ruling more leniently.
So, if you are Sephardic, then all is still parve, as long as the knife was clean. If you are Ashkenazi though, you may have a problem. The hot chili peppers became "meaty" by being cut with a meat knife, and then they will have made the soup meaty, unless they were nullified by having 60 times their volume of soup to cancel them out. So, accordingly, your soup, pot, and stirring spoon are all meaty. However, some opinions argue on this point, and hold that the meat taste in the peppers is not strong enough to come out and make the parve pot forbidden (see the Even Ozer, Yoreh Deah 96). If we add this doubt to the argument about whether the "sharp" foods extract the meat taste even from a knife that had not been used in the last 24 hours, we have two serious doubts that can be combined to make a leniency and consider everything still parve.
Therefore, (if you are Ashkenazi and have this doubt) I would suggest to kosher the pot and spoon by boiling water to nearly overflowing in the pot, and then heating the spoon on the fire till it is very hot, and dropping it into the pot so the water overflows the top rim of the pot (this way you kosher the pot and the spoon at the same time – even though just heating the spoon in the fire, or just putting it in boiling water alone would kosher it, by dropping it hot into the pot it will make the water overflow when it is still boiling, and kosher the top rim of the pot). If however you are unable to kosher them, because they are made of a material that cannot be koshered, or for some other valid reason, you could rely on the leniency I wrote above, and consider everything still parve.