What happens if you switch to 18 hour light 5 weeks into flower with 3 to go?

Would there be any growth, or would it just be better to chop them early?
Problem is my cucumbers want more light.

No they will stop budding and re-veg. And week five is too early too chop.

Let’s see a pic of what you got.

If we're talking weed pretty much nothing good is going to happen, unless you're keeping them at 18 to reveg a mother plant .

Cucumbers I have no knowledge of .

Fifty cents should buy you a couple of cucumbers, stick to 12 hours

I've reveged after flower, but never during when buds are still on it.

Think I'll wait. Not certain on how the cucumbers would react too.