Verb conjugation of "vergiften" in German

My boss offered it to me, so that a few more people at work will have a good level of English and now I really have to kick my own ass (I've started last year and it's not going very well).
I am a computer scientist and I also have a small restaurant with my younger sister (she is also already 53). You can come and visit, I will buy you a drink and we could chat a little.
You need to call before you leave... When there is good weather outside all restaurants open outside and the people sit in the sun, eat and drink. The lake is also very romantic in the late night.