My father-in-law has 2 allotments and we all work on it together.
For the last 2 years he has been getting most of his plants started off in the green houses at home and he uses the cardboard tubes mainly from inside toilet rolls. he makes them square so he can get more on a tray and we plant them straight into the ground. it worked fine last year and were doing the same again.
also we found if we left weeds we had pulled laid down between rows, they helped to retain some of the moisture in the soil in dry spells. they can encourage slugs to stay under the damp weeds and away from the crops.
Just thought I'd share that.
I'm probably telling you what you already know
