[Subversive_plot]

In my effort to get courgettes started early to beat the squash vine borers, I'm wondering how cold is too cold?

Near-term, moving them indoors at night as needed should be no problem. Mid March though, we may have nights that dip to 5 C for an hour or two in the early morning, warming later to 15 C.  Can seedlings cope with that, or is it too cold?

Put another way, how cold can seedlings tolerate?

Thank you

[mumofstig]

Could you just try a couple of plants and cover them with fleece/plastic to stop them actually freezing. I used to see garden plots full of them, covered overnight in the early spring, when I lived in Greece.
Certainly worth a try for that early crop IMO 

[Grubbypaws]

In my experience here in the north of the UK it is only a late frost that they cannot tolerate. I plant them out when there is still a chance of a late frost but make sure that I have something to cover them with if one is forecast. One year I even put a tent up on the lawn; it worked fabulously! last year I was a bit more conventional putting them under a cover of fleece with my container grown potatoes. That worked just as well 

[Subversive_plot]

I could do that.  My plan was to grow in large containers again, I could just leave some "head space" above the soil in the pot and cover that.

Do you recall if those fields in Greece ever dipped to 5 C or lower?

Curiously, the seeds I am growing come from my cheapest seed brand, American Seed 4 packs for 1 dollar.  They germinated fast, in days the roots are already out of the bottom of the pots. Labeled as "Dark Green Zucchini" and "Early Summer Crookneck".  Growing better than much more expensive seed.

[mumofstig]

Do you recall if those fields in Greece ever dipped to 5 C or lower?

There would be the occasional night when leaf edges of Oleanders were blackened, so must have been 'chilly' what the actual minimum temp was, I don't know.

[AndyRVTR]

I know of locals on Rhodes, Greece where temps can get down to 0⁰c, but that's more in the mountain regions.. they have the odd snow shower lower down, even on beaches but no freezing temps and they seem to grow veg OK!

[Subversive_plot]

Thanks for the advice everyone!

Last year my diary page records that I had female blossoms by May 16.  This year I'm hoping the weather is favorable, and I can beat that date by a few weeks!