Why are my courgettes knobbly?!

[sweetcorn]

One of my green courgettes and both of my yellow courgette plants are producing smallish, knobbly courgettes! The yield has been disappointing - certainly no glut! I have been feeding them carefully. The yellow ones are planted in raised beds with plenty of manure incorporated and the green one is in a pot. Any clues??

[womble]

I had this last year with a yellow courgette, I presumed it had picked up some kind of virus.
It started giving yellow/green, wrong looking courgettes, I still ate them though

[sweetcorn]

Yes, we've been eating them too, but they're not as big as they should be, or as prolific. They taste fine! The leaves show no viral probs.

[Toby]

My mum had this problem last year. She was using water that had been through a water softner, when she stoped and used water that had not, the courgettes immediatly returned to normal.

[sweetcorn]

Do you think water butt water would have the same effect??

[Pies]

Could do rain water and softened water are very similar

[toastie]

Have been using rain water (from a water butt) to water ours and haven't had this problem. Ours have been growing like wildfire - pity you weren't closer to the Black Country or you could have had some as been giving quite a lot of them away. Have also been feeding them with tomato feed - they are in the same raised bed as some of the tomatoes (grew them in the same bed last year albeit a different one). Perhaps they've got a virus. Did you grow them from seed or buy them as small plants and transplanted them?

[Luci]

My courgettes are just beginning to go knobbly.
They've been producing normal ones until the last couple of days.
I just thought that the plant was beginning to run out of steam, and was producing the last of the courgettes!!