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Dublin, Ireland

Hello, if anyone could lend any insight it would be great

I cannot get my female flowers to establish fruit set. I have been trying all summer, and female flower after female flowers just wilt away.

We grow in very large containers. The plants establish and make plenty of flowers.

I am growing two varieties, pot-of-gold and some standard grocery store variety of jack-o-lantern pumpkins. There are 3 of one in one container and 2 of the other variety in the other container. (see photo):
<a href="https://ibb.co/n36m74y"><img src="https://i.ibb.co/xmXL1wb/20190806-113124.jpg" alt="20190806-113124" border="0" /></a>

I am aware I have some serious downy blight, it is nearly impossible to prevent without chemicals in Ireland. It wasnt bad before, it got a lot worse in August. Had it before but had pumpkins.

At the beginning of the season in April I had ALL female flowers. This went on for weeks. Males arrived and I began rubbing stamens on stigmas.

At first, and Ive never seen this before: The stamens had NO POLLEN on them. Completely bare, right after the flower had opened. Insects?

That eventually resolved and the stamens started being covered in tons of pollen:
<a href="https://ibb.co/58jVV5W"><img src="https://i.ibb.co/zR2wwSh/20190807-182510.jpg" alt="20190807-182510" border="0" /></a>

I have done this a dozen times. All of the fruit has not set and has rotted off:
<a href="https://ibb.co/99fYpKS"><img src="https://i.ibb.co/TBnhwjd/20190806-113106.jpg" alt="20190806-113106" border="0" /></a>

There are still female flowers arriving, but I am essentially out of hope here.
<a href="https://ibb.co/XzVmkK7"><img src="https://i.ibb.co/br7pRCs/20190806-113159-1.jpg" alt="20190806-113159-1" border="0" /></a>

8/7/2019 3:26:07 PM

Dublin, Ireland

SORRY, here is the same post with working links for the images:

Hello, if anyone could lend any insight it would be great

I cannot get my female flowers to establish fruit set. I have been trying all summer, and female flower after female flowers just wilt away.

We grow in very large containers. The plants establish and make plenty of flowers.

I am growing two varieties, pot-of-gold and some standard grocery store variety of jack-o-lantern pumpkins. There are 3 of one in one container and 2 of the other variety in the other container. (see photo):
https://ibb.co/n36m74y

I am aware I have some serious downy blight, it is nearly impossible to prevent without chemicals in Ireland. It wasnt bad before, it got a lot worse in August. Had it before but had pumpkins.

At the beginning of the season in April I had ALL female flowers. This went on for weeks. Males arrived and I began rubbing stamens on stigmas.

At first, and Ive never seen this before: The stamens had NO POLLEN on them. Completely bare, right after the flower had opened. Insects?

That eventually resolved and the stamens started being covered in tons of pollen:
https://ibb.co/58jVV5W

I have done this a dozen times. All of the fruit has not set and has rotted off:
https://ibb.co/99fYpKS

There are still female flowers arriving, but I am essentially out of hope here.
https://ibb.co/XzVmkK7

pH? Cross-pollinating between plants and they are incompatible? Any insight would be very much appreciated.

8/7/2019 3:32:19 PM

Bloomington, IN USA

Try fertilizing with a high Phosphorus Bloom Booster fertilizer.
I had the same problem with an Atlantic Giant.
I had 7 female blossoms that I pollinated & every one of them just rotted off.
I thought either the plant is sterile or P is low.
Did a tissue test...Low P.
10 days later, after supplementing P, I had 5 little pumpkins.
Good Luck!

8/7/2019 10:44:30 PM

Grittyville, WA

I dont know if it could be that you are using C pepo on a moschata or maxima or vica versa. Check the seed packets for the species. Growing with a limited root system will exacerbate some nutrient problems, like calcium. There may be a smaller quantity of nutrients to begin with... plus its easy to over or underwater... I think either could cause aborts.

8/8/2019 1:33:57 AM

Bethlehem CT

In pots it is absolutely critical to keep the soil moisture even, Often times potted plants get root bound and the soil dries out very quickly after a watering. Sometimes the growing media especially if it contains lots of peat or humus can start to become Hydrophobic (Resists water absorption) The stress of fluctuating moisture levels can cause the fruit to abort. Are your plants drying out between watering? To the point where the leaves are wilting? If so it could be water stress that is causing your problem.

8/8/2019 7:32:47 AM

Bethlehem CT

In pots it is absolutely critical to keep the soil moisture even, Often times potted plants get root bound and the soil dries out very quickly after a watering. Sometimes the growing media especially if it contains lots of peat or humus can start to become Hydrophobic (Resists water absorption) The stress of fluctuating moisture levels can cause the fruit to abort. Are your plants drying out between watering? To the point where the leaves are wilting? If so it could be water stress that is causing your problem.

8/8/2019 7:33:29 AM

Bethlehem CT

How big are your pots? three plants is an awful lot to have in one container. Unless it is truly a massive container.

8/8/2019 7:34:30 AM

Guelph, Ontario

Have you been able to grow fruit with this many plants in a pot this size before? Those pots are awlfly small for one pumpkin, never mind 3 plants.

8/9/2019 4:44:13 PM