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I'm stoked to see this thread started (even if I might not have my stuff together to join this year)!

For anybody thinking about growing giant pumpkins, I'd recommend Chad New's youtube channel [he will send you giant pumpkin seeds if you send him a padded mailer and a nice note]

Would also recommend Howard Dill's (yeah, that Howard Dill) website if you just want to buy some. Dill's Atlantic Giant® Pumpkin -Premium Seeds 2008

Some other giant pumpkin growers I enjoy following (not everybody posts every year, but their video archives have loads of useful info):

https://www.youtube.com/@docrodebaugh

https://www.youtube.com/@growinggiantswithscott4130

https://www.youtube.com/@NortheastGiantPumpkin

https://www.youtube.com/@jeffsgiantgrowingjournal6003

https://www.youtube.com/@travisspumpkins7682

https://www.youtube.com/@josiahbrandt150

https://www.youtube.com/@MobyMikePumpkins

 

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I learned a hard lesson about soil temperature last year. I started plants indoors around 3/19 and put them in the ground on 4/29 thinking I was getting a jump on the season. Well those plants did jack squat for a very long time and I'm pretty sure it's because the soil was just too cold for them to uptake nutrients efficiently. The chart below is nominally for germination, but it stands to reason that seeds wouldn't sprout until the conditions are right for them to grow well. I measured my soil temps today and they were 49F in the ground and 55F in the raised beds (and that's in SoCal). So I'm going to hold off a bit this year even if it means battling the heat again trying to get a pollination to take. Plus that gives me more time to get some soil to fill the raised beds I just built last weekend.

 

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Great chart! I have always heard that ground temps needed to be 70 for pumpkins. Pretty cool that your chart backed that up. It's just another reason why an early start is hard. I remember the year I was gung ho about it. I installed soil cables, a hut with a ceramic heater and fan. I still don't quite understand why a fan on low makes it hotter. UnOx tried to explain it to me, but it still hurts my head. IIRC, heat settles at the top and the fan distributes it around the enclosure. I think he mentioned that his workplace runs the giant ceiling fans in the warehouse even during the winter for that reason.

I think you're totally right about the fan helping with warmth. Another advantage of the fan would be for disease prevention. Seems like all the "pro" pumpkin growers have fans constantly blowing on both the stump of their plant as well as the leaf canopy.

 

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In a bit of a panic after reading that pumpkin seeds won’t germinate in soil colder than 18 degrees C (mine were in a Scottish greenhouse for four days after planting 😥). So in my desperation I’m now heating them up.

Come on ma wee beauties!

Can't help but read that without a solid Scottish brogue. Good call bringing them into someplace warm. I think you want to be shooting for ~29C for good germination probability. If the pumpkins don't work out though, you can always go the Celtic carved root vegetable option.

 

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I'm switching over to an olla watering system in our garden, just finished the first raised bed (tomatoes/salsa garden) All the soil work put in last year is really starting to show results in that one. Thinking we'll try olla watering with pumpkins in bed 2 as well with soil work going on in beds 3 and 4 and construction on 5 and maybe 6.

Cool! I hadn't heard that term before but had seen the terra cotta vessels and it now makes sense. I just installed a similar system last weekend that uses 4" perforated drainage pipe wrapped in a fabric screen with a pond liner (forms the water reservoir) to make a wicking sub-irrigated planter (SIP). No clue if it will work or not. But given the price of peat moss and coco coir, it had better work or my wife is going to be really pissed. 🎃

The 2x4s are just there to space the pipes while I worked the coco coir in between and then I pulled them out. The "good" soil goes on top of that initial wicking layer.

 

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Wasn't sure if I'd make it this year, but I'm in the ground (er, elevated sub-irrigated planter raised beds). Starting with two pumpkins in each bed (will cull to one plant per bed): 717# Connolly and a 1643# New running south, and another 1643# New and a 678.5# House running north. I know it's bonkers to put these giant seeds in a 4'x8' raised bed. But I've never had much luck getting roots along the secondaries to take hold. So if I can just support the vines enough to keep them from kinking as they descend from the bed to the ground then I'll still get photons into the leaves but the nutrients will come from the stump in (absurdly over-engineered) raised bed soil. 🤞

 

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Okay, so I'm still trying to grow squash on the low desert, and after many fails, I have several squash plants that are thriving, including a red kuri that is producing blossoms. I have one single fruit the size of a grape tomato, and I've never gotten this far before, so I'm thrilled. We're entering the 100 degree days this week, so I don't know how long the squash will make it.

I've tried (with very limited success) to put 1 and 2L frozen water bottles into a styrofoam cooler from the grocery store surrounding the fruit. Have to cut slots for the in and out of the vine and replace the bottle once or twice a day. Fingers crossed for you though.

 

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Here's my plan this year and you all can tell me if it's crazy or brilliant. I've got two giant pumpkin vines running in opposite directions in two elevated self-watering 4x8' beds and I need to get the vines down from the ~39" high soil level to the ground. I've built a wood "off ramp" for the main vine to support it on the way down and I'm running strings down to stakes in the ground to support each secondary. I'm using those little tomato vine clips to guide/support the secondaries as they gently glide down to the ground.

At least that's the plan on the front side. The back side is up against other raised beds and the wall with the neighbors. So it's gonna be a mess back there.

 

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But, I have 4 baby raccoons lumbering around my yard and countless groundhogs because I live on a river. I’m hoping pumpkin isn’t food for any of them.

I think raccoons are mostly carnivores/ insectivores. So the problem I've had with them a few times hasn't been deliberate damage to the plant but collateral damage as they completely dug up the soft soil full of juicy worms. A couple years ago I had one really smart one that defeated all of the physical barriers or scary motion-activated props I threw at it. If they know there are a bunch of worms just sitting there, they're going to find a way in.

 

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Okay guys, I have some more questions!

1. I’m still a bit confused by vine burying - can you only bury specific parts of the vine? For example, I was earlier recommended to bury the section of vine where the female flower is removed. Is this the only place that burying can be done?

2. At what point do you stop removing the female flowers/ wee pumpkins and start pollinating? How large should the plant be?


3. Also, I have a huge bag of coffee grounds that I was considering sprinkling on top of the soil. Is this safe to do? I hear pumpkins need a lot of nitrogen, so I was thinking of fertilising 2 x per week, with a sprinkling of coffee grounds every month. Any thoughts?

Thanks again guys!

1) Couple vids on the subject of vine burying from youtubers I follow:

Punchline is that the additional roots will come out of the top and bottom of EVERY leaf node. So you want to put some soil top and bottom and make sure it's moist to get the roots sprouting. There are other goodies you can add to help as well. Just make sure your secondaries (and any male flowers you want to keep for pollination time) don't get buried.

2) Personally, I leave the female flowers until I have a solid pollination where I want it and then cut off the ones I don't want. Reason is that quite often it gets too hot to pollinate where I want the fruit, or I break a vine, or critters get at it. So unless I'm sure I've got a solid pumpkin going, I leave them. But the answer to how long of a plant will depend on how big of a pumpkin you are trying to grow. The giant growers want 16+ secondaries behind their fruit. But that's a really big plant and I certainly will take a good pumpkin wherever I can get it.

3) I think there's a risk of putting uncomposted coffee grounds directly into the soil near plants but can't recall why (acidification maybe?). If you're really trying to add NPK + Mg + Ca + micronutrients, I'd use actual fertilizers than relying on coffee grounds alone. But if you've got a compost pile, I'd definitely add them to it.

 

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So far so good on the pumpkins in the elevated beds. Of course we're heading out for summer vacation right when the female flowers are just showing up. Come on bees!!! Do you thing. 🤞 I've been using the Masterblend fertilizer kit weekly and the vines and leaf stems are a lot more yellow than I'm used to. But can't argue with how well things are growing.

 

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Monday is my best bet with a high of 83 degrees then it is 88/89 as far as the eye can see. On the bright side, still below 90. While I have never had frozen water bottles help with pollination, I will probably get a dollar store styrofoam cooler and play with my new temp gauge this weekend.

I am curious if I use a gallon jug of frozen water what the inside cooler temp is and how long it holds.

I've found a solid 10+ degree difference between the interior and exterior air with frozen water bottles and a styrofoam cooler. I would expect the bigger the bottle, the longer it should last (compared to multiple bottles of similar total volume) since the surface area to volume ratio will be lower. But it may not get as cold for the same reason. I'd make sure the young pumpkin isn't making contact with the frozen bottle though.

You may want to cut notches in the styrofoam in a few strategic places for the in/out vines to run so the cooler can lay flush with the ground to keep the wind from dragging out all of your hard-earned cool air.

[<-- I love the the HF says that I'm "Registered" in Belgium, even though I'm just posting from there while on vacation.]

 

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I tried to get everything set up for the two pumpkin plants before heading out on vacation a couple weeks ago and saw a female flower on the main vine starting to form on the "off ramp" of one plant. So I positioned some chairs to catch the pumpkin and shade cloth to keep it cool and crossed my fingers that the bees with take care of pollination. A family member swung by to make sure all was well and it looks to me like there's a pumpkin under that shade cloth. I'm stoked! Going to have a lot of vine organization to do when we get back.

 

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Got home from vacation to mostly good news in the patch. Went from zero pollinated pumpkins to about 10x bee-pollinated pumpkins (largest about the size of a soccer ball) and have a ton of female flowers on secondaries ready to bloom. Plenty of aborted pumpkins on the vine too, but I'd say >50% pollination (thanks bees!!!). Tried to organize the vines (broke a couple) and it'll look like a mess until the flowers figure out which way is up again. Unfortunately, our weather couldn't be worse this coming week. So I'm going to protect everything I can (both pollinated and yet-to-be-pollinated flowers and see what makes it through the week before I start culling the extras.

 

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Small update from my own patch. I seem to have a few viable pumpkins growing, albeit slowly.

Lots of potential there!!!

I noticed that it looks like the blossoms are getting removed from the end of the fruit not long after pollination. Not sure if they are falling off naturally or they're getting pulled off by a person/critter. Personally, I'd avoid removing them by hand since it's an easy way for disease to into the fruit. I pull the flower petal parts off after a while (especially if they are keeping that end moist and prone to diseases) but leave the lobed nub in place and maybe paint it with some alcohol to dry it out. It'll crumble off naturally as the pumpkin growth comes to an end.

 

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The bad news:
View attachment 778442

We might have to deal with hellish heat here is SoCal. But I can't tell you how glad I am that SVBs don't live around these parts.

 

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Hopefully not premature, but my largest pumpkin is now on a 3'x3' platform that's 20" off the ground. Those of you that followed the 2021 pumpkin growers thread will note that lessons were learned from that year (when my 285 lbs pumpkin was more than 5 feet off the ground and I had to build a gantry to get it off there).

2021:

 

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View attachment 778654

I like your "calibrated size reference object". I admit I use a beer bottle/can because it makes the pumpkin look bigger. Fingers crossed that those pollinations took!

 

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My big max, now with 5 baby female flowers...

Looking good HH! Unsolicited advice here: start trying to get those vines with the females off the fence and closer to the ground on a hot day. Otherwise you'll either need to A) build a support for the pumpkin, or B) accept that when that pumpkin gets heavy it's going to tear off that fence and break the vine. It's totally fine for secondaries to climb up (I'm doing that as well). But it comes at the cost that they can't sink roots into the ground to draw more nutrients to get bigger/more pumpkins.

 

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The heat has killed most of the female flowers this past week. But the pumpkins that were pollinated before it got really hot are still chugging along for the most part (though some are doing better than others). My largest fruit is officially large enough to put a bottle next to for scale (yes, I still have a couple cases of pumpkin beer from last year).

I'm probably getting ahead of myself, but I'm trying to buy some "mill fabric" from Alibaba to put my pumpkins on. This guy will easily weigh a couple hundred pounds by the time it shows up though.