I use toilet/paper towel rolls and they go in the soil and rot down, so the roots don't get disturbed. They're easy and cheap to use.

Or youi could make youre own by wrapping a piece of newspaper round a broom handle, or similar piece of wood. Once again, this can be planted in the ground and the paper will rot away.

Thanks both. I have read some commentators complaining about fungus on the toilet rolls. Anything in that?

No direct experience but I thought that the fungus of toilet paper tended to be living off the glue that holds it together and not the plant material.

I have root trainers but I'm lucky to be able to buy from a seed box run about a local allotment society. Mine were fairly cheap to buy - personally I think they are worth every penny as you sow the seed eg a bean or pea, you water from the bottom and you end up with a real sturdy plant with a fantastic root system. I know there is the initial outlay but I was mine after use and they are fairly robost this will be the fourth year of using mine. I was them in diluted jeyes fluid at the end of season!