Growing potatoes in a barrel

Reading Mollison's intro book there is a brief section on growing potatoes in nothing but mulch inside a barrel--filling it a little, adding the potatoes, and adding more mulch as they grow. Has anyone tried this with any success? Mollison doesn't go into much detail about it. I'm wondering how broken down the mulch should be, how often to water, etc.

My question about this method is how do the leaves get light down in the barrel?

For more than 40 years now, I have been making compost piles using 2x4s and tied horse fencing. The piles I make are 4-foot cubes. This year I'm going to try a 4-foot cube entirely devoted to potatoes. I have plenty of maple leaves on my own place, and access to all the spoiled hay and straw I can handle. Plus I have a lot of comfrey.

Google "potato tower" and you'll find a lot of info on this approach to growing potatoes. I've never tried, but it's on my to-do list -- some folks do appear to achieve very good yields this way, especially given the small footprint. My understanding is that the mulch doesn't really need to be broken down. I'd be inclined to start with a layer of potting mix and a good dose of organic fertilizer, plant the seed potatoes, cover with more potting mix, and then layer the mulch as they grow.

from my limited experience growing them in deep compost/mulch you really need to have a well composted bed. I was using more fresh types of leaves and grass clippings. It worked ok for potatoes but seemed to work better for sweet potatoes. FWIW.

I'll add that I have had good success growing potatoes under mulch in the garden. I plant and cover the potatoes, and, instead of hilling with soil as they grow, I add successive layers of wheat straw. I read about this many years ago, and it's a great way to grow potatoes if you want to minimize soil disturbance.