[Kajazy]

I read somewhere that you're supposed to pinch out the growing tip of trailing varieties of squash/pumpkin/cucumber - is this correct? If so, does anyone know when, where and why?

[Trillium]

Pinching them out stops them growing any longer and turns the energy back into sizing up the existing fruits on the vines.

It's more common for pumpkins and squashes. For pumpkins you can limit it to about 3 fruit, or if you're competing, one fruit. Squashes is more a matter of how many do you want. Pinch the tip off when you get the quantity you want.

Cucumbers can be pinched back but they'll not produce more fruit and the existing ones can grow too large and bitter to be tasty so unless you've had your fill of cukes, you might prefer to let newer, fresher cukes grow and pull off the older bitter cukes.

[galen]

I would add that for outdoor Cucumbers both Dr H's book and the growing section on this site say you should pinch out the growing tip when between 6 - 8 true leaves have formed to produce more side shoots for fruiting 

[Trillium]

Must admit that I never bother pinching out my cucumbers and my neighbour now runs when she sees me coming with another armload 

[Stratts]

How about pinching them if they grow up a munty frame?  I have 3 going well at the moment.  Oh and 2 gherkin plants on there too in place of my only suicidal cuke plant!

Ta

[mumofstig]

pinch them out it you want extra branches, leave them alone if you'd rather they made taller plants.

[Stratts]

Thanks I think I'll pinch the gherkins then, as more shoots should equal more gherks & won't matter if they're smaller coz it'll make it easier for picklng