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Nashville, TN

I've received donated 'privately grown' GP seed from so many sources!! THANKYOU!!! Couple more questions... (those of you just coming in on this - I am doing a study of heat tolerance in TN, currently have 20 GP varieties that I'm starting the study with.....)

#1 Have white varieties as well as Orange/red. Does color seem to affect heat tolerance of the fruit itself?

#2 Do the white varieties need sun protection sooner than the orange/red?

#3 At what size do I need to put up sun protection?

#4 What size would be the best to go through and 'cull' the excess pumpkins off of the vines for maximum growth?

#5 What sun protection systems are the most effective - my engineer fiancee' has been looking at all of the pictures on the seed packets we've recieved - and there are numerous examples.........

3/29/2005 1:14:21 PM

Goffstown,nh

#1 All colors tend to be effected equally...
#2 All colors need sun protection at the same time.
#3 I usually start considering protection at beachball size.
#4 At 70"-80" circumfrence, and when I feel confident that I have my best choice going on the main vine.
#5 Some folks just put a white sheet on them. Myself i fabricate rounded tent shape structures that are very wind resistant.
Good Luck...

3/29/2005 2:00:13 PM

Phoenix, AZ

Since you are studying heat resistance, I have a few questions:

What will determine thermotolerance?

How will you confirm this tolerance is specific to a particular line of seed as compared to one seed?

Very interested as you move forward. If you need heat, I have lots for you!

3/29/2005 8:36:50 PM

Napa Valley, CA

Scienceteacher..... you mentioned that you are doing a study of heat tolerance on 20 GP varieties.
Keep in mind, as you start this projcet, that there is wide range of heat resistance within the AG variety alone. Here is an example.....
Last year in my pumpkin patch I had 2 AG's planted about 25 feet apart. They both were planted in the same type of soil and recieved about the same amount of sun, heat and water. Both were from seed stock from the Northwest. They had a common but not an exact AG genetic background. One plant was highly heat resistant and stood up well during the mid-day heat while the other was drooping earlier in the day when the temperature was 10 degrees cooler.
Some AG's are more heat resistant than others. This is not an uncommon occurrence.
I think that heat resistance is a complex issue with many factors to consider that would require years of serious study with a tremendous amount of plants before definite conclusions could be reached.
Hey, we gotta start somewhere......good luck with your project.

3/30/2005 1:16:57 AM

Syracuse, NY

i would not use WHITE SHEETS as SUN protection..
or, more properly worded, "protection from the sun"...
anything that will mostly if not fully BLOCK the sun's rays
would be appropriate. my cautious words, though>>>my 632.5
from '02 grown off of the 845 Bobier '00 was getting pretty big and i finally put super-sun-protection over it;
a 4'X 4' piece of 1/4" plywood on top of four posts,
the back two hinged for easy lift-up access.....
she started turning green as soon as i did this. matter of days. so, i would say the best thing is something that
is a happy medium, but BLOCKS the sun, doesn't INVITE it, like a white sheet would......medium blue to dark orange to..........eric

3/30/2005 1:38:31 AM

New Hampshire

Eric, I think you have it backwards, White reflects light not absorbs it.

3/30/2005 5:49:44 AM

Ontario, Canada.

Forget about black landscape fabric as it will absorb far too much sunlight and get very hot. If it touches the pumpkins surface it can cause it to scorch on the contact site. I had this problem in 2003. Check out the link below.

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=13669

Last year I used a few green 5' x 7' tarps which worked very well.

Russ

3/30/2005 7:31:37 PM

Appalachian Mtns.

White keeps things cooler/reflects heat than a darker color....compare a white car vs black car in the Summertime with the windows rolled up, you'll see.

3/31/2005 7:10:46 AM

Nashville, TN

Thermotolerance will be indicated by the following:

1. Lack or timing of fruit cracking/splitting (at which time it will be harvested, weighed on scales, and recorded)

2. Timing of fruit maturity.

3. apparent heat stress shown by individual plants will be noted daily.

We are even debating putting Thermo-couplings inside each pumpkin to see if air temperature, sun exposure, shade, etc. Has a corresponding increase/decrease in actual internal temperature. Though this may have to wait until the second year/further study. I would have to research ways of doing this technique - and then ask the Engineer to design the system.

Thankyou for the advise on the shading devices - I will have to do a temperature study on those methods this month to see which to utilize....

3/31/2005 1:59:21 PM

Nashville, TN

Hotpumpkin: If you want to include your plot in this, I can send the extras of the same varieties, as well as copy the study 'recording forms' as well... but it'll take more time than just growing... You'll have to spend 10-20 minutes twice a day recording your rain fall, high-low temperatures, daily climate, as well as condition of each plant...

Feel free to email me - though You're climate would fall under: study of heat tolerance in an arid climate... Though mine is: study of heat tolerance in a temperate climate.... so our results may be different due to soil, climate difference....

3/31/2005 2:04:13 PM

Menomonie, WI (mail@gr8pumpkin.net)

Just how are you going to put a thermocouple inside a pumpkin? I can see a thermocouple externally placed, but would not put one "Inside" the pumpkin. You would be better off using another method of measurement. Such as a non contact infared thermometer.

3/31/2005 2:30:19 PM

Phoenix, AZ

Teach,

Sounds like stuff I do anyway, just don't currently record it. I will get with you.

3/31/2005 2:48:13 PM

Nashville, TN

Now I'm not an engineer... but apparently you can install two little wires into the interior of an object.. seal it with just a touch hanging out.. then go around with just one measuring device...

Apparently you can get everything at radio shack for under $50... Much cheaper than infared equipment..

Though this is my Fiancee's domain **grin**

3/31/2005 5:01:16 PM

Utah

yup a thermocouple is just two wires ...
we pumpkin growers don't typically like the idea of poking holes into pumpkins...
if you do they would be more susceptible rotting.
... I don't know if a small hole would heal over well or not ?

3/31/2005 5:30:56 PM

Garden State Pumpkins

Love the project! Don't like poking an air hole to the cavity when it might cause the demise of a large pumpkin. Not sure but you might get away with one early on. Shade protection is more to keep the skin of the pumpkin elastic when they out grow there normal leaf covering a "suntan" will harden the outside skin. If the skin cracks with a growth spurt the pumpkin will surely suffer. the protection also keeps the water from sitting in the cracks..another demon to the fruit. While internal temperature might cause a blossom end blowout I think most would agree it's not the internal temperature but the external conditions...I hope you get more posts from this as I think your project is exceptional and well needed by all of us...come on guys we need your opionions. Grow Em Big! Chuck

3/31/2005 6:49:04 PM

Eugene, OR

Cool ideas here. I'm a math/science nut so I'm always interested in using a scientific approach to solve a problem. How often were you considering collecting thermocouple data? If you do decide to use thermocouples to measure internal temperatures, I think using multiple thermocouples embedded in the flesh at various points in the pumpkin instead of in the cavity would be beneficial to take thermal gradients into account. Should eliminate the problem of rot as well I would think.

This is just screaming for a simple computer data acquisition system program. You could use the CDAS to collect multiple data points at a chosen interval and let it interpret the thermocouple temperatures for you based on the voltage readings instead of having to use the thermocouple tables. One big problem I see that will definitely affect your results is the fact that during the day, the outside temperature is constantly changing. When the ambient temperature changes, so does your thermocouple reference junction temperature. Because of this, the accuracy of your data will go down the more the reference junction temperature varies from the inital temperature used to get the reference junction temperature/voltage reading. You need to constantly correct the thermocouple readings for the change in ambient temperature but it's definitely a feasible project to undertake with nothing more than a laptop, a bit of instrumentation, and a simple CDAS program. Collecting your data by hand would definitely make it less complicated but constantly having to calculate the temperature using the thermocouple voltage reading and the reference junction temperature will get old real fast.

Sounds like a project I would be very interested in working on. If only there were more than 24 hours in the day! LOL

Good luck!
Brian

3/31/2005 7:17:29 PM

Syracuse, NY

it's a long weigh down the page here, but i meant that a white sheet doesn't really do anything to stop the bright sunlight from coming through, so the more impermeable-to-light that it is the better, up to a certain point...eric

4/1/2005 5:33:23 PM

Nashville, TN

I wish Brian in Oregon was closer! Discussed the thermocouplers with the resident Ag Engineer (Fiancee') For this year he is happy to assist in designing and setting up 'shade covers' - but he feels that doing thermocouplings may have to wait until next year...

Might 'test' a couple of the Big Max's this year by putting 'test wires' in them and recording what they do. That will give us more insight into how to put couplings in these giants.....

Now if Brian wants to start on some sort of software program for recording specific data pertaining to GPs - I could test it at the end of the growing season by plugging my data into it... If it works easily - maybe the study could be expanded in '06 - to cover many growers and hundreds of GPs?????

4/5/2005 1:48:55 PM

Pumpkintown, SC

I am curious as to the "20 GP varieties" you are speaking of? Is this 20 "strains" of Atlantic Giants? Is this 20 "pepos"? Is this 20 "maximas"? Please advise...
Also, since there is so much variation from seed to seed from the same pumpkin(no matter the variety), how many pumpkins will be represented and how many seeds from each of these fruit? Sounds interesting. I hope you have the time, means and most importantly, the fire within to see it thru. I don't know you from Adam or should I say Eve, and I don't know how many seasons of AGs you may have under your belt, but please take this as "constructive" criticism when I say, "start small and grow from there". These guys require a lot of time and effort just to see them through an entire season. Good luck again and don't give up. Lord knows us southern boys could use some "thermotolerance" educating. BF

4/6/2005 12:58:52 AM

Eugene, OR

I would be happy to send you a copy of one of the CDAS programs I already have when you get to the point where you think you need it. I totally agree with BF though. I grew 4 plants last year(my first) and I had a hard time keeping up with them. I can't even imagine growing 20+ plants like quite a few growers do!

Good luck with your experiments!
Brian

4/6/2005 1:41:51 AM