I think that a lot of it depends on the individual nurse, but I think a minimum of 6 months hospital or LTC experience is the least, better to have 1-2 years of general nursing experience. The rationale for my opinion: Nursing school generally does a good job of preparing you to sit NCLEX and gives you just enough knowledge of Ivory Tower Nursing to land a beginning job. It does not generally prepare one to be a independent provider. In that beginning job, you hone your skills, benefit from the experiences of your coworkers (good and bad), and develop your independent judgment. You learn how to manage your time, your attitude, and how to negotiate interpersonal relationships with other nurses, aides, therapists, physicians, etc. You learn when something just isn't right and you learn what things you can let go of and which you need to hold dear. Most facilities provide an extensive training program on policies and procedures, since few students run into every conceivable P&P during school.
Home health, on the other hand, is *not* a beginning job and requires a very independent practitioner. You usually will not have someone right there with you to whom you can turn and say, "What is this funny heart sound?" You have to be able to trust your judgment and your skills and sometimes your intuition. You need to have experience with assessing patients of all kinds, in all kinds of situations. And to me, a big part of it is that when you've had experience in hospital, you know what sorts of care the patient is likely to have received--and not received. As hospital nurses, we do the best we can, but in areas of patient education, there's almost never enough time. Because of time constraints, the stress of hospitalization, med changes, etc., few patients come out of an acute stay with the kind of patient education that they need. That's a big gap that home health fills. Then there's the supervision angle. Unless you've had supervisory experience in your previous career, you need to learn the delicate art of supervision other nurses and nursing assistants. A couple of years in hospital or LTC can help prepare for that. There's a lot to home health, and I would suggest that anyone who is interested in it might try to see if they can shadow a home health nurse for a day or two, to get a good idea of the mix of skills required.
So that's my two cents' worth, do with it what you will.