Harvesting sweet potatoes

[Daddy Pig]

I have three sweet potato 'vines' growing in large sacks in my (unheated) greenhouse. They're still growing with healthy green foliage all over the place - how can I tell when they're ready to harvest?

[Alison]

The foilage won't die down or anything so as far as I know the only way to tell is by digging down and seeing. You're further south than me but with the predicted frosts then I'd have a look soon as they won't survive any frost what so ever. Would be interested to know what sort of crop you get as I've not really managed anything the the two years I've tried - last year the slips arrived too late and although I got off to an early start this year with cuttings from last, I put it down to the weather being so bad as I understand that they need a long summer period.

[chickenjane]

Dear Alison, Can i ask how you keep/what you keep in order to get your own slips for next year?

I've got some beauregard & somw T65. the foliage got cut down by frost 2 nights ago so I'vr lifted the B'regard. A few decent size tuburs which surprised me as they were in the plot in a raised bed & not under cover.also arrived v late so probably not planted out till 3rd week of june. So in theory get 'em in earlier & have a better summer & bob's my sweet potato harvest.

Ps do I have to 'cure' them

Dear Daddy pig, as far as I know you leave em in the ground for as long as poss. you canleave em in after foliage has been frostd off,though can't se what it would achieve unless there's a maturation that swetens them up or something. But they must be lifted before you get a penetrating frost as that would destroy the tubers. I've just lifted one of my 2 beds, generally rather small,but a couple cheered me up. You never know , there might be a decent harvest in there.
could you come & report back on here?

[Alison]

Sorry, can't help you too much with regards what to do with the tuber, I'm not sure how long they keep (not long in our house!) but suppose you need to dry them out a bit first otherwise they'd go rotten.

All I've ever done is taken cuttings from the greenery bit before the frost has got them and then simply dipped them in rooting compost and into small long tom pots and then let them do their thing in a cool but frost free conservatory over winter. Then potted them on in the Spring before planting up early summer and treating as the previous year.