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Deer Park, WI

I didnt want this to get passed up in "how to make flesh" thread below. I think this is important information for growers to understand. So here it goes-

Most of you probably understand the conept of sources and sinks. Leaves are sources: of water and sucrose, the building blocks of pumpkins. Sinks are sucking up all these goodies to be put to use. Sinks include root tips, meristems, fruit, and reproductive stuctures (male & female flowers). This is important- Growing a huge fruit requires that it be THE PRIMARY sink on the plant. Given the list of sinks, there is fierce competition for the sugar and water sucked up by the roots. Plants have a way of ranking which sink gets the goodies. Its an enzyme called sucrose synthase (SUSY). Basically, this little guy converts sucrose into starch. Starch becomes pumpkin. The more sucrose synthase a sink has, the more goodies it gets. If logic serves you well, then it states that the more SUSY a punkin has, the bigger its gonna get. So the question becomes how does one increase SUSY? That aint so easy, unless you start manipulating genetics. However, there are other ways to alter sink strengths. The first and most obvious is to limit the number of sinks on the plant sucking precious juices from your prize pumper. Prune your vines!!!! This is a no brainer. Less meristematic tissue=lowered sink #'s continued....

11/21/2003 11:25:10 AM

Deer Park, WI

As for roots, those we want. Dont go pruning roots or anything like that. How bout multiple fruit? Check this out- "The number of fruits set per plant has a great impact on the dry matter partitioning and fruit growth" taken from "MODELLING FRUIT SET, FRUIT GROWTH AND DRY MATTER PARTITIONING Authors: L.F.M. Marcelis, E. Heuvelink" So it serves to reason that limiting the number of fruit per plant will increase sink strength. Not revolutionary thinking, but this time its backed up by science. Another one...pruning those extra males and females WILL make a difference. The plant puts a lot of energy into making 100s of male flowers. Nip them off before they develop, especially after fruit set. It is worth the effort!!!
On a slightly different note, this text was also taken from the above referenced article "Several experiments have shown that fruit set increases with source strength and decreases with sink strength" Source strength=available nutrients. And it appears that fruit aborts could be due to very high sink strength. Imagine if those fruit took off?!

Back to the main question, what is pumpkin flesh? As explained above, its a mix of most starch and water. A pumpkin is 85-90% water. Now, what is the most important nutrient we can give a fruit to maximize size? WATER. You can play with calcium, N-P-K, uranimum, einsteinium all you want, but when it comes to packing on true size, water does the job. Research suggests that you should not let your plants dry out. This increases Abscissic Acid production, a plant hormone that will ultimately decrease sink strength and cease growth. Consistent watering eliminates this problem. Hope this helps folks, if you have any questions shoot em my way.

11/21/2003 11:38:24 AM

Western NY

that's darn interesting. now i have a question- what's in a pumpkin? what i mean, is what makes up the "air" space that is the seed cavity? if it's pure oxygen, we could just stick a fuse in them, and run. so, it's not pure oxygen, or someone would have already tried that one. CO2?, or is it the same mix as the outside air? if so, how does it get inside? i don't believe it can diffuse through the skin that fast.

11/21/2003 11:49:14 AM

Utah

joe-
in regaurds to male flower pruning... I have wondered about this.
Theoretically it makes sence to prune them. but maybe the reverse is true? what if there was a trigger associate with how many flower the plant has grown. i'll expanded on this later...
with males i think experience has shown that it doesn't matter either way.

the next questions is... what about the female flowers...
are they a sink ? theoretically yes. in real life ????
i'm not so sure maybe yes and no at the same time.
there has been some talk about the plant shifting modes from growing mode to mother mode. this maybe trigger in the plant occurs when a certain amount of fruit have been set. Weather and time of year are also influences that can not be ruled out.

I've read posts that said that you want to keep setting as many females as possible after your "main" fruit to keep the plant in mother mode ... that after this time if you cull all the females off before they are pollinated the plant goes back to grow mode to produce more females.
this could help to explain why recently there have been some plants with two large fruit. maybe more than one "main" fruit is better.
also it is known that vines with fruit on them increase in size dramatically. so the question is do set a fruit at the end of every 2ndary, and father down the main to help the "juices" in the plant flow better ?
if so how many to set? every 2ndary ? every other ?
many many do you want to set on the main ?
how big do you let them grow?
when and how often do you cull them? all at once? one a day?

so what's the point of all this...I think there are triggers in these plants that we are just begining to explore, that we are just starting to glimps onto. That for the most part we have found by random luck and chance observation. so experiment a way keep your eyes open and see what happens.

11/21/2003 12:38:09 PM

Itzetown City

Joe,to sink or not to sink? I sink that is not the question. The important sink i sink is, the most of sink will be waste by building seeds. Its not recommend to build up to 400 - 500 seeds p.pumpkin. Most of them will end one way ore another in the hand of these damned hoarders. So up to 10 seeds p.pumpkin will more than enough. If there were a way to limit the seeds the recource could use by flesh and the result bigger pumpkins.

11/21/2003 1:11:09 PM

Nova Scotia

from my first year experience i pollonated everything leaving them all on for a week befor culling (12-15) then after choosing one (first one pollinated) i removed all female and male flowers. along with that i watered my plant 3 times a day for 1/2 hour each time and i truely beleive that setting all that fruit on then removing along with the large quantities of water i used is how i got my 900lbs which, if not for my mistake would have reached 1066lbs. as well my fruit grown in a hot climate were fruit should go light went heavey (OTT estimated for low 800lbs). thanks for the great info guy's

11/21/2003 2:22:56 PM

Itzetown City

Mr.T the Bahamas is an other sink.
The prediction of hurricanes is advice for the pumpkin to grow thicker walls to build better shelter for the seeds. Notice, the more hurricane preditions the havier the pumpkins.

11/21/2003 3:07:11 PM

Nova Scotia

you might have point boehnke. she alway's put more weight on the closer one got. lol

11/21/2003 3:31:02 PM

[email protected]

It is no secret that there are hormonal triggers that can be influenced by flowers. So manipulating them by pruning could well regulate growth to some extent. But when & which is not clear here. At fruit set? Several days later? Basketball size? Only males? All flowers?

My question with respect to Joze' concept is: At what point does new flower production become a sink? And are they ever a potential for source?

It would seem to me that at some point, all flowers should be removed. Leaving the patch for 8 days this summer I came
home to a LOT of flowers. They weighed a lot. Nearly as much as a sink.

Are we also saying the plants respond to rapid & dramatic atmospheric pressure changes? Atmospheric pressure changes in the patch by artificial manipulation doesn't sound terribly practical. But do we know which hormones are being influenced by all these flower & pressure changes?

This is a fine thread you started here Joze. Good stuff.

Steve

11/21/2003 4:46:30 PM

In the shade - PDX, OR

Awesome Stuff Joe.

This is what the off season is all about.
Keep it up.

11/21/2003 5:31:32 PM

colorado

Is it possible to develop the air space to be flesh in any way?

11/21/2003 5:52:09 PM

Stouffville

so you got two potential 1000 lbers on a plant...two black holes for the pumpkin plant's production. you cut one of these puppies off, where the hell is that juice going? is it just gonna try to grow tons more suckers or what?

11/21/2003 7:20:23 PM

[email protected]

Below is a copy and paste fest I did with all the very interesting questions. This thread has wheels turning in my head. Read this cliff note version of my favorite lines from this thread..


also it is known that vines with fruit on them increase in size dramatically. so the question is do set a fruit at the end of every 2ndary, and father down the main to help the "juices" in the plant flow better ?
if so how many to set? every 2ndary ? every other ?


so what's the point of all this...I think there are triggers in these plants that we are just begining to explore, that we are just starting to glimps onto.


My question with respect to Joze' concept is: At what point does new flower production become a sink? And are they ever a potential for source?



Are we also saying the plants respond to rapid & dramatic atmospheric pressure changes?


Is it possible to develop the air space to be flesh in any way?


you cut one of these puppies off, where the hell is that juice going?

11/21/2003 10:54:29 PM

wilmington,ma.

What direction do the juices flow off the main?Out or in?
If theres a fruit 10ft. out on a secondary, and you cull it do the juices go back to the main and next fruit???

11/22/2003 12:14:47 PM

Deer Park, WI

Wow, lots of questions. Thanks for the paste fest Rocky...makes things much easier for me! In regards to "plumping" up the vines by setting the fruit at the ends of them, i dont see how this would be beneficial. That process takes time, which means you'd need to leave the fruit on their most of the season. Counterproductive in my eyes.

New flowers, regardless of sex, are a sink from the very first cell. Flowers develop from a meristem (vine tip), which is a sink. They continue to develop until they die. Throughout this proceses they are signicant sinks.

I have no idea if pumpkins respond to atmospheric pressure changes..interesting.

The air cavity in a pumpkin is somewhat of a mystery. Just how does that air get in there??? I have not come up with a evolutionary advatage to the large air cavity in a pumpkin. any ideas?

When you cut of a vine, or pumpkin, or flower, the juice is redirected to other sinks. The plant knows how to do this.

Juice does flow both ways in a plant. Nutrient and water motion carried out by pressure gradients and osmoality. Water first flows into a leaf, sugars and water then move out of the leaf, into the vine, and towards a sink. Also, there is real life proof of this in my own patch. My 1056 was set early on the main, 10' out. I lost the majority of the leaves in front of the fruit to PM early Sept. The fruit continued to grow 5-8lbs/day the rest of the season on the newer growth.

The plant shifting modes, in my opinion, is primarily due to daylight influenced hormonal shifts. However it is possible that fruit set or lack thereof could signal some changes in the plant.

11/22/2003 1:47:22 PM

Nova Scotia

does having more sink's cause a plant to increase it's sources? so if you put on a lot of pumpkin's (sink's) on , then cut them off. would this not create more of a source to put into 1 sink?

11/25/2003 12:52:22 PM

Knopp, Germany

Joe, it was explained to me from someone that went on the Hew Hampshire Patch tour this year that most NH growers took great pride in making sure that there wasn't any flowers in the patch, not a one. Also, that the stump areas seemed to be clear of any secondary vines for the first couple of feet, (means that there obviously wasn't the chance for any so called "secondary mains" which could possibly use up uneeded energy). He also noticed that every other secondary was removed, and lastly, and for me the most interesting and not understandable was that the main vine and all vine growth after the pumpkin seemed to be pale compared to before the pumpkin, and that the plant seemed to know where the pumpkin was. Any thoughts? thanks, owen

12/1/2003 8:14:10 AM