If my deal with my Gardener is that I pay him for the month and he comes once per week and he decides to come on Shabbos this week, do I have to make a Macha’ah and tell him not to do his work on Shabbos?
"the work being performed by the non-Jew may not involve things that are connected to the ground, such as buildings or crops....
The non-Jew may not even chisel stones or prepare boards for the building in public if it is known that they belong to a Jew. (Some authorities permit this so long as it is not known that the work is being done for a Jew – Rema 244:2. If the lumber or stones belong to the non-Jewish contractor, it is permitted so long as he does not do so on the Jew’s property – Mishnah Brurah 244:14.) Similarly, one may not permit a non-Jew to plow, reap, or otherwise work in his field even if they set a predetermined flat rate."
Essentially, any work on a Jew's property is assur, and farming and gardening are also separately forbidden.