How skilled are you at managing an operation such as ours? Can you give an example that would help us to understand your managerial skill level?
In this line of questioning the interviewer is looking for the specifics of your demonstrated, repeatable greenhouse or nursery management skills. You may think it's a simple enough question but unless you portray confidence and address their importance to the overall tasks they're a part of, you're not going far enough with your answer. Chances are also pretty good that the skills will be a very necessary part of the job you're interviewing for. Be sure to pay attention to describing how you acquired and practiced the skill, over what time frame, how easy or hard it was to master and whether this is something that you enjoy doing. Your response should be detailed and fully explained, yet brief. Too much information can be as bad as not enough.