Growing sweet potatoes in England

Margaret emailed allotmentblogger@gmail.com to ask what I knew about growing sweet potatoes. The answer is virtually nothing! But I do know a man who grows them, so I wandered along to talk to Andy, whose allotment work is supervised by a seagull called Henry who shares Andy’s lunch and will eat from a fork (I kid you not!)

Apparently the key thing here is to get some organic sweet potatoes if you’re using supermarket stock – because most of the other ones they sell have been treated in some way to stop them sprouting. It’s not that easy to get seed tubers of sweet potatoes in the UK, but Andy doesn’t even bother, he just grows supermarket tubers.

He lays them lengthways, half-covered only, in damp sand over a heated base tray to promote sprouting in early March and this causes ‘slips’ to grow and when they are four or five inches long he breaks them off and pots them into 1 litre pots. Other people grow the slips by setting the lower half (generally more pointy) of the tuber in a jar of water on a windowsill apparently.

Then in late May or early June, once all risk of frost has passed, he sets them out into a sunny trench. Where they go insane! It takes at least 110 days for them to mature and because they are Ipomeas (morning glories) they spread out like jungle plants and tend to take over nearby areas. Keep them warm, keep them watered but don’t worry about pests, it appears they don’t really have any – a bit of wire worm in late tubers is about all he’s seen, he says.

Dig them up as late in September as the good weather permits, then put them in a greenhouse for a week to let the skins cure and the tubers sweeten and Bob’s your uncle, apparently!

Now this is all based on growing in the South East of England, and shouldn't be taken as a guide to anywhere else, but if you treat sweet potatoes as a semi-tropical plant, I think you'll do okay

Labels: allotment-greenhouse, allotment-sweet-potatoes