Some activities are just plain bizarre. And growing potatoes in containers, when you have a perfectly good vegetable patch, seems like one of them. Especially as they have less space to grow and need more watering.
So, when my husband came home with two packs of these Haxnicks' potato planters (pictured) I had to bite my tongue. No point in discouraging food production, even on a bijou scale.
But would it be bijou? Floating around the Internet is the suggestion that if you earth up a potato plant well enough, it will send off more potato-producing shoots, or stolons, and you’ll get a much bigger harvest, distributed throughout the container.
The idea seems to stem (hah, sorry!) from a piece in The Seattle Times. In 2005 Greg Lutovsky was quoted as saying that, when growing potatoes in a box, you could “steal” the tubers from the bottom of the box (removing the bottom slats, then replacing them) throughout the season. “Unless you steal all of them during the growing season, in the fall you should end up with a box of spuds—as much as 100 lbs.”
This sort of thing is not well received among those whom you’d expect to know. The RHS, in its April 2011 edition of The Garden wrote, “Contrary to adverts, potato plants only produce potatoes around 12 inches below the soil level.” Earthing up would not, they added, increase yields.
I spoke to potato expert and grower Alan Romans. With Colin Randall of Thompson and Morgan, he conducted his own experiments at Capel Manor a few years ago. “Just a disaster” is the way he described it, and thinks that the weight of compost squeezed air out from where it was needed. “The potato is a modified stem tuber; if anything it needs more air than normal tuber.” It’s possible that the very wet summer affected results, but all they turned out of the containers were “malformed potatoes, very disappointing”. The way to get a large potato harvest is “deep cultivation, loads of space and loads of fertilizer,” added Romans.
It’s worth bearing in mind that commercial growers do everything possible to increase their yield, yet manage around 25 lbs of crop per lb sown—considerably less than the tantalising prospect of 100lbs from a four-foot box. Nevertheless, the idea sounds plausible, and is so deeply appealing – all those spuds and no digging! – that it’s sparked numerous experiments among garden bloggers, especially in America.
Come back for the next instalment, when we look at how they’ve got on.