Kitchen Garden Forum

Hi all,

I saw the spread about Chantal in the KG mag - congratulations Chantal! I note that you got good sweet potatoes, so i thought I'd try to show you mine. It seems they need moisture rather than tropical heat, though doubtless they'd have done better in a warmer summer.

I put a lot of compost on the soil of a raised bed , and warmed it up to 14 degrees with black polythene. I got 12 slips from the Organic Catalogue, of which 10 survived, and planted them out in June.

In early October this is what I got from one plant:



Ultimately I ended up with 8 productive plants, most of which produced bigger but fewer tubers. They rapidly lost the deep red colour and I don't suppose I cured them particularly well, but they tasted good and, although it's work, I'll have another go at them next year.

mike

I should have added that I gave them at irregular intervals a drink of comfrey or nettle "tea". It may have helped.

mike

Hi Mike

I think you did better than me When Steve saw my sweet potatoes he was looking at all the lush growth on the top a month or so before we tried digging them. Underneath was absolute rubbish as Seedling will testify (so were her's ). I'm not going to bother again; somebody yell at me if you hear me mention I'm thinking about it.

Well done with your crop.

Hi Mike
As Chantal so kindly pointed out my sweet potatoes were rubbish. Total waste of time and i wont bother growing them again either

Seedling

We didn't even have the excuse of them being sat on this year either

Thanks friend
Seedling

Did you by any chance just let the foliage trail along the soil? There are two books I have which give conflicting advice, but one of them says that if you allow the vines to root themselves into the soil along their length, the plant's energy is dissipated, as it is trying to produce tubers wherever it has rooted. So it is recommended to lift up the trailing shoots from time to time.

However, the other book advises not to support the vines on poles, as they won't form roots. Maybe that book is referring to the main stem, which I had planted very deeply.

Perhaps I've just been lucky.

mike

hi mike
I planted them through black plastic and let the tops trail along the plastic .Didnt lift them up at all.
Seedling

Me too

Ah, now one of the books I've got says that if you do that the plkants won't form the roots which develop into tubers. I don't quite see how that squares with the other advice of lifting up the tubers from time to time. Did you plant the slips very deeply? I made ridges and planted into these so that only the very tops of the plants were showing.

I'll post again with the details of the books, and which one says what.

mike

I followed instructions issued by T&M when I bought some a few years ago. It worked the first time but not since. I'd be interested in other methods.

OK Chantal, I've now got the books in front of me.
"Growing Unusual Vegetables" by Simon Hickmott says "the tubers can't be planted through through slits, as they are formed where the trailing stems make contact with the earth". There is an illustration [b/w drawing]showing tubers forming at the first and second nodes of shortish trailing stems.

Matthew Biggs's Complete book of Vegetables says "Occasionally lift vines from the ground to prevent rooting at the leaf joints,"

This book also encourages keeping each trailing vine to 2 ft long by pruning [I didn't] and to give the plants a high potash fertiliser; excessive nitrogen encourages stems rather than tubers.
[I alternated comfrey with nettle tea, so I was giving both. Maybe I should have stuck with the comfrey only].]

I got the Hickmott from the Organic catalogue. I din't know where the Biggs book came from, as it was given me as a present.

Anyhow the upshot is that 2 different writers seem to be giving contradictory advice. I wonder whether the solutioon is that if you plant the established slip really very deep, as recommended, the nodes of the stems nearest the main stem are already underground and so will root . The rest of the vine can then be prevented from forming too many roots. Of course, in the tropics they'll form roots and tubers very quickly, but here we've just got to expect a smaller yield.

Good luck both of you.

mike

Thanks Mike, that's nothing like what I was doing The odd thing is that I planted them through black plastic on the first year and dug up loads of them.

I don't understand

I'm still not sure I'll try again, but at least I have another method to try if I do have a go.

Cheers