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I'm getting plenty of flowers, and about half of them produce a tiny little pumpkin.

However, after only a couple of days, the pumpkins begin to turn black and shrivel up.

It is 104-degrees during the day with medium humidity.

I have been providing water.

Although my sample size may be a tad small, it seems that those in the shade are slightly more likely to survive.

Should I cover the young pumpkins to give them a chance?

I have 8 larger pumpkins in the patch, but I haven't had any new ones take hold a while.

enter image description here

More Images Here (imgur.com)

Brian Webster
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  • Are the seeds from a packet, or last year's jack-o-lantern (or pie)? – baka Jul 14 '11 at 19:23
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    Not sure where the seeds came from, part of a quantity-based pumpkin growing contest. I've been posting chronological pictures here. You can see that there's healthy pumpkins growing, but a distinct lack of young ones (perhaps due to the heat) http://punkin2011.blogspot.com/ – Brian Webster Jul 14 '11 at 19:27
  • Could you provide a little more info: What do the stems and leaves look like before and after the pumpkins turn black and shrivel up? What do the pumpkins look like *before* they reach this stage? A close-up of the whole plant would make it easier to diagnose the problem.. – Mancuniensis Jul 15 '11 at 01:59
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    http://imgur.com/a/zLWNW#zsYIp This is an image album from this afternoon; 103 degrees. All pictures of of the same vine. Sorry about the grass, I'm scared to yank it out due to the risk of damaging the vines. As you can see, I should probably set up some sort of tent over my plants. I also noticed today that the last 4-feet of one of my long vines is dying off. It's the longest one and gets the most Sun. – Brian Webster Jul 15 '11 at 19:27
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    @hamlin11, removing that grass (& other material) from under your vines would greatly help the overall health of the patch. Though I agree with you on *"I'm scared to yank it out due to the risk of damaging the vines"*, next time you will be better prepared :) Also judging from those photos I would say you need to get some organic matter in there (feed the vines). Without a doubt getting some shade covers (or similar) & protecting them from the midday sun, with temperatures you are currently experiencing, will most definitely benefit the overall health of your patch. – Mike Perry Jul 15 '11 at 20:57
  • @hamlin11, I agree with Mike - your soil looks pretty hungry :) and in need of humus; if it's light, some farmyard manure would do it a power of good, if it's heavy, I would give it plenty of horse manure. – Mancuniensis Jul 16 '11 at 02:11

2 Answers2

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With 104°F temperatures and especially if your pumpkins are in full sun, that is the most likely cause of what you're seeing.

Also did you allow the patch to dry out during that extremely hot period?

If yes, that would also have had an affect on what you are now seeing.

  • Pumpkins, especially early on when fruit is being set, benefit greatly from some protection from the full midday sun (especially when taking into account the kind of temperature you gave) ie Think shade covers.
  • Pumpkins are heavy feeds, plenty of organic matter and fertiliser (if you can't get enough good quality organic matter).
  • Pumpkins do better with a good constant water supply. You don't want to be drowning them, but keeping the soil constantly moist below the surface, greatly helps keep them happy. It's better to water at soil level, instead of from above. Drought, drying out of the soil can really stress your pumpkin patch.
  • Pumpkins like and need a lot of space, and also like their patch weed-free as much as possible. Careful, regular, hoeing of your pumpkin patch is a worthwhile job, your pumpkins will thank you for it. Added benefit of keeping your patch as clean as possible = Greatly reduces the risk of pests/disease taking hold.

I think you might find the first 10 minutes or so of the below podcast worth a listen:

Mike Perry
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5

Judging from the latest photos you have posted, which show that the entire plant has yellowed, and the leaves have wilted, I suspect that the problem could be caused by the fungus Fusarium Crown Rot, which has not yet spread to your other pumpkins, as outbreaks tend to be localized; the symptoms develop as follows:

  • Initially, the leaves and stem turn yellow

  • Over the next 2-3 weeks, the entire plant wilts, collapses and decays.

Apparently, damage to the fruit varies widely,depending on the particular pathogen involved. It is worth examining the stems carefully, since a black and rotting area, at or just below the soil line, is characteristic of this disease, and together with the above symptoms, would definitely suggest FCR.

I hope this tentative diagnosis prove wrong, as its spores can survive in the soil for 2-3 years and, unfortunately, there is no way of controlling it other than by a four-year rotation.

You will find most of this information about FCR, together with details of similar diseases, here and here

Mancuniensis
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