A green-thumbed friend gave me a tip. Apparently we have a severe shortage of bees in Adelaide at the moment so I need to self-fertilise the pumpkins. Which basically means sticking your finger in the boy pumpkin flower to collect some pollen and then brushing it in the girl pumpkin flower. Which is which? Easy. The male flower is long and pointy and the female flower is round and curvy. Ofcourse!
And we've had success! This is a butternut pumpkin which I grew from seeds I collected from a shop-bought pumpkin last year. Pumpkin soup here we come.