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27 Dec 17 Phil Morton (Australia - temperate climate)

Are pumpkins short-day plants? Mine are spreading all over the yard, but there are still no flowers. I've forced early flowering of other short-day plants by covering them in black plastic every second evening and keeping it on the next morning to create a twelve hour night for them and it's worked well, chokos being a good example, but I can't find anything to suggest pumpkins react the same. If no one has the answer I suppose I'll just get myself some black plastic and try for myself, but with some 40'C days around I'm hesitant.

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30 Dec 17 Mike (Australia - temperate climate)

I think you are on the wrong track with length of daylight hours. I have plants growing now. Just hand pollinated a dozen or so female flowers last week. My vines are 4m+ long. Maybe you have given them too much Nitrogen. 40c would probably cook them under black plastic.

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07 Jan 18 Phil Morton (Australia - temperate climate)

Well I don't know if it was just coincidence and time for the pumpkins to start flowering anyway but after five nights of covering most of the pumpkins with just a light weed mat instead of black plastic, those covered now have 2-4 male flowers on each. No sign of female flowers though! The one I did not cover still has no flowers. I put the covers over at around 7.30 pm each evening and pulled them off anywhere from 8 am to 9.00 am the next morning giving them roughly only 11 hours of daylight.

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24 Feb 18 Phil (Australia - temperate climate)

So I stopped a couple of days later with the black shade-cloth cover as described thinking I had triggered flowering, but those male flowers just died off and I did not seen another flower until yesterday, so six weeks later! Next season I'll try covering for at least two weeks if I can get a cool enough period and see what results.

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