Growing potatoes in pots will certainly make your patio more productive, but is it, as suggested by How to Grow 100lbs of Potatoes in Four Square Feet, possible to create a bumper harvest by continually earthing up the plants? The idea is that by earthing them up all the way to the top of a large container, the plants will send out far more stolons and the container will, by harvest time, be bung full of spuds, all the way to the top.
In Potatoes in Containers we looked at expert opinion, which takes a very dim view of the likelihood of this. However, a number of garden bloggers have given it a go. So, how have they fared?
Johanna Silver at Sunset (page no longer online) harvested 6½lbs of Bintje from a tower about 3 feet high, and Jim Sincock, at Landshare Colorado, managed 25lbs of unspecified reds but only from 2 towers and 10lbs of seed potatoes. Neither result is exactly jaw-dropping, and both Johanna and Jim were disappointed to find all the potatoes nestling snugly at the bottom. That's an awful lot of soil to pile on top, when the potatoes turn out to be exactly where they would have been anyway.
Sinfonian's Garden Adventure harvested 10lbs of Yukon Gold and a better 25lbs of Organic Butte. He goes into his experience in interesting detail but in the end (you've guessed it) the crop remained resolutely in the bottom six inches of the box, where the seed potatoes were originally planted. Greg Lutovsky (the one who seems to have got everyone going via an article in The Seattle Times) advised Sinfonian that early varieties don't do well in towers. Well, that could explain some of the disappointments - Yukon Gold is a Second Early, but Bintje is an early maincrop.
Of course, disappointing results don't mean that the theory is wrong. It could be the gardeners at fault. Phillip Cairns, a Newfoundland bee-keeper, and his wife, have put a lot of effort into potato towers. They've honed their methods over three years and this is the now-or-never moment. If they don't get good results this year, they're done trying, and I for one will be keeping an eye on their blog Mudsongs as he told me, "We'll update the page on our website if the mini potato tower is successful (though we have our doubts)."
You probably have your doubts too by now, but Phillip makes one tantalising comment about his Blue Pride potatoes. "We harvested many of them well above the first level of the mini-tower." Well, that's just what you want! Has anyone else managed to do this?
Rob at OneStrawRob has a post on his experiences that's well worth reading. He cossetted a Carola through an entire summer and, in another tantalising glimpse of possibilities, it produced potatoes from 2 to 18 inches above the seed potato - as he says, "Far higher in the soil than one would ever expect from conventionally grown potatoes."
So, the jury is still (just about) out; Sinfonian, whose friends have tried potato towers, notes, "I have yet to see anyone get 100lbs from one of these." But is it impossible? What about those Blue Pride and Carola?
Well, it's going to take a lot more potato-growing to find out. As Rob says: "It still may be possible -and I hope it is – but it is not easy, it is not guaranteed, and it needs alot more research and realism before anyone goes filling the internet with wild claims."
Indeed, all we potato growers could be part of a giant, if rather uncontrolled, research project. It's the wrong time to plant in the Northern hemisphere but, come Spring, I'll do a round-up of all the tactics that Rob and Phillip suggest to get the best chance of success. In the meantime, if you have any experience of trying to fill a container with a potato harvest, let us know what cultivars you grew.