Sweet potato experiment: results you’ve all awaited


How did the sweet potatoes go this year, I hear you ask? I’ve been flooded with enquiries. You’ll remember I planted them as this year’s experiment in the garden, to expand the range of what I knew how to grow.

Those sweet looking plants arrived with beard-looking roots back in May. I planted them variously. A few in growbags, like the pictures from Marshalls suggested would be an idea. I downloaded and printed off a set of reasonably specific instructions from the RHS website.

They seemed like a great source. They train people in how to garden. And my cousin also uses them as his “go to” for advice. He’d decided to join me in growing these, although I think he started much later and decided to nurture something tangible for next year.

I planted a couple in those spare old chimney pots. Then put the pots in less than the sunniest spot in the garden – probably the least sunniest actually – for something that needed more warmth than potatoes! Well, there are basic mistakes in experiments sometimes. The other plants I put in individual grow bags in the greenhouse – which should be the warmest place, throughout what was out very baking summer.

For weeks – the 12-16 weeks it said on the instructions – I waited. The ones in the greenhouse in particular showed signs of much life. I wasn’t sure how far to fill up the bag with compost. My mother said at one point “you need to get rid of that bind weed” in the greenhouse. No! That was the fast-growing plant greenery!

Were the roots putting in the same effort down below? Did the produce grow just next to the initial, slightly buried, stem? Or shoots down and grow at the ends of the roots? I’d see when I pulled them up. Which would have to be before the first frost (unpredictable, but sometime in October perhaps. Maybe not until November though) or once the leaves started to die back and become yellow.

The greenery didn’t die back very quickly. (The ones in the chimney pots didn’t do as well. I moved them to the greenhouse in the end.) I lifted earth around the top of the plant and found, yes, there was something growing.

Eventually I took some up. They weren’t big. The chunky bit was two to three inches long perhaps and up to an inch and a half thick. There were plenty of thinner longer its. The tubers didn’t go too deep into the bags. But there were quick a few of them and enough to cook.

Sweet potatoes were small, long stringed but full of flavour

So we did – after leaving them to “cure” or dry off for a couple of weeks. Just as the instructions had suggested. Roasted up, as we tend to do with sweet potatoes, they tasted….floral? I know many vegetables taste different – stronger, fuller of flavour – when grown at home. Like carrots. They seem to lose flavour somewhere in the process from farm to plate.

Not these sweet potatoes, certainly. Maybe that is how they are supposed to taste. Maybe it was the variety I went for, which is supposed to grow in the UK. The flavour will just take a bit of getting used to. It was a pretty strong taste akin to soapy, but not nauseating.

The use of space and compost? It seems a huge amount for what was a small yield. Regular potatoes were far more plentiful per bag. And I grew some of those in the ground. And whatever you grow it does tend to do better in the earth. A plastic cover is recommended for that method, with slits in it so the plant’s greenery can shoot out of the top, but it keeps the warmth in on those colder summer/early autumn night when the blasting daylight heat of summer has dissipated.

There were several plants in my packet. So a couple are still in the greenhouse and we’ll see whether an overwinter helps. Maybe they won’t survive at all. Maybe next year I’ll use the growbags for something else.