Sweet potato - through black plastic, or let them root?

[ourarka]

Calling all successful sweet potato growers - just wondered which of the following you have found gives more satisfactory yields?

1) Allowing the spreading foliage to root in the soil, so creating lots of tubers.

2) Preventing the foliage taking root (e.g. growing on a plastic membrane) so that all the tubers are concentrated at the original planting point?

Has anyone noticed any discernible difference, or swear by one in particular? I know the plastic may have other benefits (such as warming soil, preventing moisture loss etc).

[ameno]

I grew them through black plastic outside at my allotment this year, and got 5kg from three plants. They grew far and wide, though, stretching far beyond the area covered by plastic.

I will say, if you are thinking of growing them in bare soil because you think they will root along their length and produce more tubers, think again. Even in suitably warm countries, those roots along the stems are more just for providing extra water and nutrient than for tuber production, and in this cool, dull country that goes double. You will never get any worthwhile tubers from those roots. Best case scenario will be a few rat tails.

I would recommend growing through plastic if you can, not specifically to prevent the stems rooting, but because it warms the soil, retains moisture, and suppresses weeds. And unless you get a really good summer, fewer, larger tubers is usually preferable, as lots of small tubers is likely to lead a a large number of tubers so small they are not usable.

[Thelma Sanders]

And unless you get a really good summer, fewer, larger tubers is usually preferable, as lots of small tubers is likely to lead a a large number of tubers so small they are not usable.

I grew them in the ground but undercover a few years ago, and all I got was small unusable tubers - despite feeding and watering - so haven't ever bothered again.
Good luck if you try them!

[ameno]

I grew them in the ground but undercover a few years ago, and all I got was small unusable tubers - despite feeding and watering - so haven't ever bothered again.
Good luck if you try them!

Variety counts for a lot, too.
I'm growing T65, which is by far the highest yielding in our climate. It's a drier, starchier variety, though, so some may not find it as tasty (personally, I prefer it, though, as I find the sweeter varieties to be too sickly).

[ourarka]

Thanks all - interesting to hear your experiences. I have actually been growing them fairly successfully for a few years but always failed to take notice of what worked best (!) so interested to see what others were doing.

I’ve grown a variety of varieties (is that good grammar?) and actually haven’t noticed a huge difference. I didn’t like the taste of the T65 so probably will steer clear of them, despite them being good do’ers.