I planted 14 Dickinson pumpkin in January and 10 of them germinated and have grown into beautiful wines. Fruit are forming but soon they turn yellow and fall off. I had one pumpkin forming but eventually it also has turned yellow.
Anyone have ideas why this is happening? I have applied organic fertiliser around the base every 4 weeks or so.
I don't see any bugs around except for one type (see photos) - but it doesn't make any visible harm to the plants.
I am in North Thailand. It's hot and dry at the moment.
Mark, it seems possible to me that pollination could be your issue, or rather lack thereof. Plants don't like to waste energy on fruits that have no or poor pollination (no to few seeds inside). Have you tried hand pollinating? Generally take a male flower from one plant, touch it to make sure it's shedding pollen, and then rip it off, tear off the petals, and rub it against a female stigma from another plant. Female flowers have a mini squash at the base of the flower (ovary) and male flowers have none, plus they shed pollen.
Sometimes plants abort because of resource issues. Too much nitrogen can trigger vegetative growth over fruiting. Too little of something like water can limit reproductive output and could lead to abortion potentially.
I had a couple moschata (same species as Dickinson pumpkin) plants on the edge of my patch that didn't get watered well because of a dry farming tomatoes experiment adjacent that only produced male flowers last summer. Watered patch was very productive though.
Western Montana gardener and botanist in zone 6a according to 2012 zone update.
Gardening on lakebed sediments with 7 inch silty clay loam topsoil, 7 inch clay accumulation layer underneath, have added sand in places.
I have now tried to hand-pollinating one morning. I mostly have a lot of female flowers and had to do some searching before I found two males. I attach a photo of how it looks like. First time I have ever done this so not sure I am doing it right and if the male flower was shedding pollen.
I will also water more extensively. Let's see if it helps 😊
Diego Footer on Permaculture Based Homesteads - from the Eat Your Dirt Summit