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Grittyville, WA

I've always felt like 70% of the plant was doing 90% of the work, maybe in some cases, 50% of the plant was doing all the work. The rear near the stump is where I suspect no contribution is being made to the pumpkin.

First, is there any way to verify this? Scientifically...?

10/24/2022 5:31:03 PM

Grittyville, WA

Second, does the extra square footage have some benefit? When&where&what is that benefit?

10/24/2022 5:35:33 PM

Lodi, California

How do you know these leaves aren't doing anything for the pumpkin? Is it possible that these leaves are feeding the roots more than the pumpkin? Are roots necessary for a big pumpkin? I don't know, these are just the questions that came to mind.

Also, those leaves are older, so I suspect they would be past their prime come August-September. That doesn't necessarily mean you should remove them. If the leaves aren't causing a problem and they're still photosynthesizing, then there's really no reason to remove them.

10/24/2022 9:29:43 PM

Grittyville, WA

I think there are three problems, if indeed the resources arent making it into the pumpkin. Yes, the resources are probably going into the roots, or perhaps they just stagnate or contribute to a blown stump?

First, it gives you a false sense of accomplishment, because a huge plant where some parts arent contributing, gives a somewhat inaccurate hope of getting large pumpkin. Second its a waste of effort and garden space and water and fertilizer. Third, if you could get the plant to grow that extra plant mass somewhere else--somewhere that would actually contribute--then you are maybe missing that opportunity to do things in a better way.

Probably beating a dead horse, I know this has been discussed before.

10/24/2022 9:54:05 PM

Grittyville, WA

I guess to answer my own question:
Growing a pumpkin on a scale, and then cutting off the suspected moocher vines, and seeing if that changed the trajectory of the growth, compared to the current trajectory and the expected trajectory. This would give an educated guess as to which vines were contributing vs (theoretically) just mooching. It would still just be a guess, because there are too many unknowns about how the plumbing and contribution to the overall plant works exactly, but it would be a start.

There have been less deliberate anecdotes, about losing this much of the plant" but "still getting (xx) lbs per day". But I dont think anyone has deliberately studied it.

In other words/in summary, I could grow one or more sacrifice-to-science pumpkins, on a scale, and just start pruning!

10/24/2022 10:08:32 PM

Lodi, California

I don't see how any vine with leaves on it could be a "moocher". If it's photosynthesizing, I don't see why it would be a net negative.

10/24/2022 11:20:29 PM

Torrance, Ca.

The Patons, Daletas and Travis grow 1500 plus sq foot plants. They do this for a reason. I feel all healthy leaves help with growth,,, especially healthy leaves at the end of the season.
The main goal for the plant is to reproduce and send all its energy to that fruit. That's as scientific as I can get.

I do know the Patons and Daletas water the back half ( where the stump is ) less later in the season. This has been tested through Steve's underground water probes that show that part of the plant is not needing the water it did early in the season. The newer growth then gets more water as the seasons hits mid August.

10/24/2022 11:47:38 PM

Grittyville, WA

If a 150 ft plant (probably 250 when the total leaf area is measured) can produce 1300, then that suggests the largest plants may be larger than necessary. When I say mooching, its more that its draining my own time/energy/budget. To me, there's a big "work smarter not harder" difference between growing a 1300 lb pumpkin on a 150 sq ft plant vs a 1300 lb pumpkin on 1300 sq ft plant. If I could hack a 1300 square foot plant down and still get the same result... that would be much easier for me. It would definitely affect how I did things. And vica versa... if I do all the work of a 1300 sq ft plant then I would like a 2k+ pumpkin. I do have a 1300 ft area. But I know what I am up against, lots of growers will fill an area that big... but it doesnt necessarily correlate with a bigger pumpkin, so this is all just a small part of understanding what works and what doesnt.

10/25/2022 1:10:39 AM

Grittyville, WA

SoCal, yes, Daletas has let some of his vines run out 40-45 ft I think. I didnt know anyone's plants were quite that big. The biggest Ive grown have been 350-850 ft and even at that size I believe a lot of the square footage was wasted. I believe smaller plants with just a bit more care would have yielded the same or better results.

10/25/2022 1:22:35 AM

Kutztown, PA

I grew an 1102 this year. I pulled the stump and five of the first secondary vines 7 days after pollination. At best the plant ended up being 400 sf and that's a maybe. The pumpkin was a slow, but steady grower but the plant endured longer than the other 3 plants in the patch. There's never a way to measure what could have been even if you through some science at it you'd only be making inferences from the data.

10/25/2022 12:00:45 PM

Grittyville, WA

I know that a trajectory isnt an exact thing. The results from such an experiment would be only semi-conclusive at best.

Can anyone think of a better way to test what parts are contributing and how much they are contibiting? Maybe a brix reading of the sap, in different places around the plant? I wont be measuring the flow of radioactive isotopes, or anything too fancy, sorry. Thats a phd for some college kid.

10/25/2022 4:10:13 PM

Grittyville, WA

I guess the anecdote that the newer growth may contribute more (based on the transpiration rate?) is a good one... but I'm not sure thats exactly what thats showing. Interesting.

10/25/2022 4:13:30 PM

Kutztown, PA

What if you tissue tested leaves/stalks of both old and new growth for glucose? That would tell you what each was producing. You could also do a before and after fertilization tissue test to see what's helping glucose production. Another Idea: Since CO2 is converted to glucose during photosynthesis, place some sort of clear bag over a leaf/stalk and measure the O2 or CO2 levels maybe at the beginning and the end or a 24 hour period. Maybe that would tell you if old or new leaves are doing more PS thus producing more glucose. "My name is Simon Barsinister and I'm going to rule the world" :) (old mad scientist cartoon)

10/26/2022 11:10:55 AM

Grittyville, WA

Thats what I meant by measuring the "brix". I used to have a brixometer. It was easy to use, dont know if it would work on plant juice. I dont have it anymore. But yes I think with the right tools and the right questions, there's still more to learn out there in the pumpkin patch.

10/26/2022 6:36:32 PM

Kutztown, PA

Gritty, I never heard the term "Brix" before. Just looked it up.
I know you probably have a big chemistry lab at your place Gritty so you can probably do the test described in this linK:

https://sciencing.com/measure-glucose-level-leaves-7560481.html

Really, the analysis method is easy enough if you have all the glassware and reagents.

10/27/2022 8:50:04 AM

Deer Park, WI

Radio isotope testing would show that any actively photosynthesizing material positively contributes to the total carbohydrate synthesis of the plant.

10/29/2022 11:50:16 AM

Kutztown, PA

Joe the question is "how much benefit do the older leaves, i.e. the leaves of the first few secondary vines contribute to the pumpkin as opposed to benefiting sinks that are closer to them, i.e. root meristem of their own. Radio isotope testing would be cool to see. then we'd know which way everything is moving and how much. What molecule would you follow? Glucose?

11/1/2022 9:26:43 AM

Grittyville, WA

Garwolf, this is a good discussion, I do think there could be a "selfish loop" where the leaves at the extremities could pump phloem into the roots and very little anywhere else, and, the xylem cant flow in reverse so those same roots cannot be contributing to the xylem flow into the pumpkin, or into the rest of the plant. In other words, if this is happening, its almost like part of the plant is not connected or if its contributing, it might be an inconsequential amount. Phloem is weird stuff its not like water in a garden hose, nor like blood in veins. I think the ways we imagine it aren't fully accurate.
I might study it more this winter to come up with a theoretical model for optimal transport. I think top growers could be getting 2k pumpkins from 400 ft areas if they understood which parts of the plant were contributing the most, and which were contributing the least.
I dont expect anyone to bother themselves with this, unless I can show some amazing result. We'll see.

11/2/2022 7:31:05 AM

Deer Park, WI

Garwolf- I'm unsure what molecule would be ideal to follow. A primary photosynthate product would be a likely best indicator. I don't know enough about radio isotope labeling to even begin speculating on what/how. I believe i've read before that once an older leaf "wears out" it transitions from source to sink. obviously bad and should be cut. knowing when that transition occurs is likely impossible to know given current tools available to gardeners.

11/2/2022 8:35:01 AM

Kutztown, PA

Like Joes said, anything is better than nothing when you're speaking of the entire plant system, fruit and all. I'm just wondering at what point does a leaf become a liability. Is there some point that a leaf and it's adjacent roots/components begin to absorb more than they contribute. Just looking at surface area, it makes sense that when a leaf is young it's producing 100% of it capability. Let's just say for grins that 25% of that goes to it's own maintenance and the growth of it's root system. As it's surface area production is reduced by aging, damage, etc. and it's now just producing 20% of capability does that mean it's taking the other 5% of it's needs out of the system or is this concept way to simplified?

11/2/2022 8:46:55 AM

Kutztown, PA

LOL - Joe that's exactly what I was thinking. You just did a better job and more to the point way of saying it. LOL I think what you read makes sense at least to me.

11/2/2022 8:50:03 AM

Kutztown, PA

Joe/Gritty,

Check this out on Isotopes:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4177546/

Interesting stuff to Science Nerds.

11/2/2022 9:08:38 AM

Grittyville, WA

Love it u guys, the notion that older leaves dont contribute as much may be correct, but does it have to be that way? Maybe they could contribute more (or age at a slower rate) if we really understood what was going on.

Its possible there are mobile nutrients, which are catalysts for photosynthesis, which get transported to the newer leaves, thus leaving the older leaves deficient. If the plant was adequately fed, then this self cannibalism wouldnt slow the older leaves down.

11/2/2022 4:51:39 PM