When I bought my place, I put in two vegetable patches - a couple of railway sleepers, digging two spades depth of dirt out, a ton or so of dirt from my local landscaper; and about $80 of compost.
Add to that, seedlings - one disaster with the first lot, but then a second batch - call it $100; some growth feed and a few tools - gloves, water efficient dripping hose things, etc.
A few minutes of my time each day (fill 3 watering cans twice a day) through summer, and less so now it's winter; and what do I have to show for it?
5-10 kg of Capscicum
5-15 kg of cherry tomato
1-3kg of roma tomato
Enough basil to choke a donkey
10-20kg of Zucchini
1.5 Cups of chili (hot)
4-6 cobs of corn
With this, I've made a freezer full of soups; frozen ingredients; and more. On weekends, my girlfriend and I eat vegetarian - our normal spend for a delicious meal is around $4 to get other ingredients - we make double quantities and freeze the rest.
At the moment, I've eaten for around 40 days (5 months * weekends) using about 80% home grown produce; and still have an excess - I would estimate at least another 40 days worth of produce is available in one form or another.
My expenses have been little. I could probably slash the cost of growing by starting from seed - it's much cheaper than seedlings. I could probably not let everything die in a heatwave and have to start over. Next year, I'll be constructing further vegetable patches on the rest of my block.
Next year, it'll also be much more of a study - I'll be measuring, weighing, and recording the raw amount of produce I'm making - I want to see if I stack up against others.
If you had told me $282ish USD makes $2431 USD of vegetables; I would never have believed you before now.
It is clear though why we stopped being a hunter gatherer society and moved over to agriculture - I simply had no idea how much of a ROI it actually was prior to this.
I wonder how many people could be convinced to join in a garden collective? Tear up the back lawns of a whole street; and have the collective plant and maintain crops. You pay setup ($300 AUD once off) and maintenance costs (Call it a dollar a day or something related to land size used, $365ish AUD per annum); and the pay off is produce. People share the workload; and can barter amongst themselves for different crops.
What else would you do if you had something with a limited scale (your ability to own and work land); but a high ROI for small amounts?
In terms of making a profit as a side job: forget software engineering - the work is hard and undervalued; forget solar panels - the payback period too slow and the upfront costs are too high.
What probably makes me grind my teeth the most; because of its illegal nature, the economics of marijuana must be staggeringly better - traded off against the risk. You cannot participate in a value-adding economy with drug crops in general - I'm not aware of many commercially viable marijuana by-products.
The value is only there by the fact it's illegal - so folks of dubious merit are no doubt making a fair amount out of it for minimal effort. This annoys me greatly.
When you contrast that with the "American dream" (or any western culture like Australia) of everyone becoming "rich" by simply working hard at your career, buying a property or maybe two and retiring happily; the idea that people who are generally stupider, less skilled but simply less risk adverse than I are in scenarios where they have much better revenue grates very harshly on my nerves.
I don't think many of the working public would like the idea either (those that aren't tempted by the idea!), if the financial aspects of were laid out in front of them.
Which, I suppose, brings me in a rambling incoherent way, to my next topic of fascination - Charles Stross and the Merchant Princes stories. I'm most of the way through the series, and utterly enthralled.
If any of the subjects in this post have interested you in the slightest; then these books are right up your alley.