pumpkin, gourds and squashes in growbags?

[penny]

A kind friend came for lunch yesterday with 12 small packets of a few seeds each of 12 different pumpkins, gourds and squashes.
Alas I haven't room this year but I wondered if I could grow them in growbags (my local somerfield is selling at £1.30ish a pop) ontop of the area of my allotment that I have covered with black membrane for this year to try to kill off the couch grass?
What do you think?
I would not like to offend by not planting and they do look very exciting. I have put them 3 to a 3" pot in my unheated greenhouse as a start.
I had planned to grow the climber pumpkin munchkin so maybe I can return the favour?

[Tigger]

Don't see why not. I grow my main pumpkins on top of my compost heaps, squashes under my beans and courgettes beneath the sweetcorn.

[Primrose]

You might be lucky. Most of these plants seem to have a fairly shallow root base so if you've got the facility to keep them well watered they will probably give you a crop. All the growth seems to be "on top" rather than underneath.

[Geoff]

I do tend to grow stuff earlier than most but I think you have sowed at least a month too soon even for London.