Have you looked into growing trees and shrubs? A small nursery may work. They don't require a ton of work and it's like having a savings account. The bigger and more mature your plants get, the more valuable they become. And it's fairly easy to propagate your plants. You really need just a few good shrubs to start with, install a good mister and drip irrigation system and take cuttings from each plant, and voila! You have free plants over and over again. You'll want a small greenhouse if you're that far north. You may also need to get a Nurseryman's License from your state. We had to get one here in TX, and I think it cost us around $100. I got the idea years ago from
www.freeplants.com. It has really worked well for us. Mike McGroarty is the guys name, and it's the one on-line marketing thing I've found that is the real deal. Great, cheap little system and wonderful people (other growers) to deal with.
I've also been able to hit Home Depot and Lowe's at certain times of the year when they are slashing their tree inventories (usually in the Fall to make room for Christmas tree sales) and literally stealing trees. I've bought 5 and 7-gallon trees such as birch, magnolias, willows, oaks, some maples and fruit trees like peaches, apples, nectarines and pears for as little as $5 each. They usually sell for between $25-$30 each. I grab as many as I can and re-pot them into larger (usually 15-gallon and sometimes 30-gallon) containers and let nature do it's thing. A little fertilizer now and then, some light pruning and a drip irrigation system do all the work. I've been able to turn a $5 tree into a $75 tree in as little as 24 months. You will need to deer-proof the area, of course.
We also own a landscape company, so we're able to take those $5 trees (after a few years) and retail them for $175 or more. Pretty handy to be able to spec your own plants into a landscape design!
We are also growing Japanese Maples, and brother, when they reach maturity we will
really clean up! I can retail a 5'-6' 'Bloodgood' Japanese Maple for around $400 (installed). I buy 12"-18" rooted cuttings from other people in Mike's group for as little as $3 each, repot them and in about two more years (we started a year ago) we will get top dollar for them. I can afford to be patient with those kinds of returns. Can I buy a $3 stock and see it shoot to $400 in 3 years? Not often. I could likely sell the 1-yr old Jap Maples now for $25-$30 each if I wanted to. Not gonna happen. I'll wait.
I also sell any excess inventory we may have direct to other landscapers in our area. I've never had to contact or solicit local nurseries to buy them. The landscapers get a good deal (they are likely re-selling my $75 tree for $175 or more after planting) and so do I.
Also, goat meat is becoming very popular in our area. They breed very quickly, are easy to raise and easy to sell.