I use big pipes cut lengthways to grow beets and carrots. But as I've said before, my carrots were hopeless this year. Despite trying 3 different types, they just wouldn't grow. 
And I didn't have a single sunflower that survived the slugs. Yours are very impressive
I had marrow tonight...overgrown courgette actually! Roasted it with fennel and chilli and olive oil and it was delicious. 
The mornings are darker now and it won't be long before I'm walking  the dogs in the dark. Speaking of which I need to get a move on!