[nobby90]

Every year if i grow Courgettes in my polly tunel they get tip rot.  WHen theyare about 3 inches long they start to rot at the tip.  Every year every plant.  However if I grow them outside they are fine.

Any ideas before I plant them out???

[Aidy]

it may just be that in the tunnel the air is just right for spores to attack where as there is more fresh air outside. I have always grown outside as they are pretty hardy for a tender plant.
If you insist on growing in the tunnel try increasing the air circulation.

[JayG]

Although the prolific nature of courgettes is almost a standing joke on this site, if they are not pollinated they will rot even though they initially get to about 3" long as you say.

This is much more likely to happen inside a polytunnel where there are few if any pollinating insects.

Even though I grow mine outside I do help them along with an artist's paintbrush!

[mumofstig]

Ah well you see........there are now several varieties that do not need pollination 

I'm trying one this year........it begining to flower indoors cos it's still too cold in the tunnel ..............maybe one year my sowing dates will agree with the weather

[JayG]

Better ask Nobby which variety he's growing!

NOBBY, Are you there?!!!

[realfood]

I am trying cavili F1 this year, which is a parthenocarpic variety. ie. it can set fruit without pollination.

[nobby90]

 This year I am giving Defender and Jemmer a go.

I usually get a good crop outdoors but try one or two plants in the tunnel for an earlier crop.

The pollination sounds a probable cause.