[Flowertot]

I have grown Queensland Blue pumpkins for the first time this year (which are similar in colour to Crown Prince) as I love their flavour.  As they don't turn orange, how do I know when they are ripe?    I didn't think of this issue when I sowed them 

[mumofstig]

this may help
http://chat.allotment-garden.org/index.php?topic=104845.msg1238131#msg1238131

[gobs]

Other than in the thread posted by Mum, I leave them out for frosts to touch them, if I can.

All sorts of melon and squash will sound hollow inside if knocked, for will be less full of water.

[pigguns]

Queensland Blue- They go sort of dull rather than fresh green (the blue/grey tinge comes in storage) -and the stalk looks 'corky', I cut my largest yesterday and did my back in, getting it to the car (8KG!)!  It's a bit early to cut it but was worried about it getting taken and some of the smaller ones are looking a bit wrinkled, their skins not set yet.  I think its the weather.  One had a gash underneath and the bugs were having a field day so didn't want to risk my big one with the wet we have planned this week.  I've left another 5 medium sized ones with hard skins for a bit longer, we should get some sun still. 
Last year I them cut the day before the first frost.  They don't go mushy and store well.  Enjoy.

[Flowertot]

Thanks very much.  4 of the 6 have gone dull so they seem to be ripening  I am going to leave them a bit longer and hope that when I harvest the 2 big ones I don't do my back in like pigguns