most of the harness you get out of a regular tack store will not be heavy enough for farm work,you will need a collar type,not a breast strap type,,and the kind of work you plan on doing will decide what type of harness you need,,there are many types,comfort is most important to the horse,a sore horse will give you trouble and not work,,a QH type horse will not be able to do much in the way of plowing,a team of QH will be better but still not what an actual draft horse can do,,,they just arent made for it,,a QH draft x would be a better choice,or a haflinger is a great choice,,I have a team of haflingers and love them,also a draft type horse has a much better mind for doing farm work,,light horses just again,are not made for it so many just wont work for that,that being said,,some would do a wonderful job,depends on the horse,but a light horse just cannot do AS MUCH WORK in a day as a draft.Fjords are said to be pretty good once you get them going,but seem to be more tempermental to me.As for getting harness,it would be best to find someone to help you if you dont know what your doing,as a green person can get ripped off pretty fast just because they are ignorant on the subject.I being from MN,,LOVE going to waverly Iowa draft horse sales,they have a website,and really,anything a person needs you can find there,and I have gotten new,never been on a horse amish made harness for about half what you would pay in a tack store.there are several sales like that around the country,maybe just google draft horse sales in your area and see what you come up with.