For the past few years I've been planting a 2 acre market garden that so far I have been able do without any chemicals or commercial fertilizer and aside from some weather issues and not being able to make enough compost to suit me, it's gone ok. To me, any kind of sustainable venture needs to include growing vegetables, any vegetables that you grow will save money at the market plus you know how your food is grown and, if all goes well it should give you some cash besides, it really is about the same as growing money. Back in my Grandfathers time it was called truck farming,I'm guessing because the vegetables were put on a truck and hauled to market and I like that name. There is a lot of thought that needs to go into something like this and if you get it started, you will probably be constantly tweaking to come up with a combination that works for you and that is the most important part, making it work for you. Education is your best weapon here and I'll be including links here or you can go to one of my Facebook pages and find links to articles that I've used in the past but the bottom line is that you really need to figure out what will work for you and then start working at putting that plan in motion. One of the biggest problems with truck farming is that most of the work happens over a couple months in the summer so if your going to make this a venture that you can live off of then you need to spread it out to as close to year round as possible. Most of the months from April to October will be covered but adding crops like garlic which around here is planted in the fall or mushrooms like oyster or shiitake that will grow with little input from you once they are started will help spread out the labor some and in the case with mushrooms, give you a crop to harvest in the spring. I've mentioned chickens before and if you can build a market for eggs and meat chickens, they can add some extra late fall/early winter income or extra spring income that can get you through the winter and give you the added benefit of eggs,meat and fertilizer. Now those chickens will have to be fed all winter even if production is down but by starting hens laying at different times in the year you should be able to keep some laying over winter plus if you can free range them in the garden through the fall plus grow a late season garden of mostly greens that will usually get you into winter at least and a fodder growing system that will keep feed costs down for the laying hens in the winter months it is workable. Looking for new ideas and figuring how to make them work in your favor is your best bet for coming out on top of any business venture and sustainable farming is no different.