Jo wrote:
I was given a couple of sweet potato plants for my birthday. I've never
grown such plants before. Any advice (ie best soil, depth etc?)

They are tropical, they need to be kept warm. They are convulvulous (sp?)
so you will doubtless get comments on your beautiful bindweed. :-)
They grow underground, so they need a fair depth of decent soil, but the
top growth really does grow like bindweed (but don't panic, it's not hardy!).
They probably won't crop as much as you want for the space they take up.

We have had moderate success growing them through black plastic or black
weed blanket (keeps it warm and moist). They like a lot of heat and a lot
of water. We normally fleece them, but the fleece has always ripped fairly
soon. This year we're trying a heavier mesh fleece to try and keep it a bit
warm.

So far our 10 sweet potato plants are still in the greenhouse as it hasn't
felt warm enough to plant out, but it's getting a bit late. :-/