I know nothing, and I'm a terrible gardener (yield wise, anyway), but if I could only grow one plant for food, it'd be the sweet potato.  They love it here in the desert southwest.  I've had plenty of failures with them (watch the video for proof), but all in all I generally do well growing them.  I went crazy this year and planted about 70'ish slips mostly in containers, and about 20 or so in the ground.  I planted two to three slips per 15 gallon nursery pot (closer to a 5 gallon bucket in size).  I haven't harvested yet since there's still some time left until my first frost.  
 The first plant I pulled was from a plastic 10 gallon nursery container?  It's about the same diameter as a 5 gallon bucket, but several inches shorter in height.  I used a mix of old potting mix I save every year, and I mixed in a bunch of my chicken litter/wood chip compost.  I fertilized with some Alaska fish fertilizer a half a dozen times up until about July, and then they just got plain water (very hard, mineralized, chlorinated, city water).   I'm dreaming of 200lbs, but I will be thrilled if I get over 50lbs, lol.  The first plant I pulled got me all excited because it had 8lbs exactly, then I pulled three other GIANT plastic containers, and only 8oz total from all three!!!  I was bummed.  
 Every plant in the yard came from three organic Stokes purple sweet potatoes I got at Smith's grocery store in February.  I started propagating them in February, and to my surprise they started forming shoots within days (first time that's happened).  I was up to my ears in slips/shoots and from those three potatoes I got probably over 150 usable shoots.  I gave some to the veterans at the veterans home I work at (super cool to see them growing at work!!!), and a bunch of others to my neighbors.  I started putting them in grow bags and plastic containers in the beginning of March in my greenhouse, then I ran out of room in the greenhouse, and started rooting them is large plastic red cups so I could transplant them to larger containers outside around May.  
 I'll upload some pics of what I actually got in a few weeks or so (first frost here).   I can't upload the iphone images from the phone I was using.
 Here's a cheesy video of my rambling about it.  I'm not too good at videos.  I did use ai for the thumbnail, and it did a great job!   
 edit, let's see if my other pictures will work.
 edit again.  I figured out how to convert them.