Temperatures that interfere with pollination

**coronabarb** · June 28, 2013

I am being questioned on my FB page about the veracity of tomato pollen becoming sterile at high temps. Also, the question of blossom drop with high night temps has come up. I know I have this ingrained in my mind but cannot find a source to back me up. I do not find it in my ultimate authority, Carolyn's book. So, do I remember correctly? Pollen becomes sterile above around 95? How do high night temps interfere with pollination? 75 degrees or so? Is it dependent on how many days the heat occurs?

amideutch · June 28, 2013

Here are a few references. Ami

http://aob.oxfordjournals.org/content/90/5/631.long

http://gardening.wsu.edu/library/vege016/vege016.htm

http://edis.ifas.ufl.edu/hs1195

**coronabarb** · June 28, 2013

Thank you Ami. Will check those out~

**coronabarb** · June 28, 2013

These are excellent! Thanks again! :-D

b54red · June 28, 2013

Anyone who has grown tomatoes in the South knows that the high temps and also the high humidity take a real toll on fruit set. Increasing the amount of water available to the plants and giving them a little boost of a liquid or soluble fertilizer will help in getting some fruit set on many varieties. Some of the hearts,black tomatoes and smaller fruited varieties have the ability to set fruit in higher temps better than most of the pinks and reds especially the large pink beefsteaks. There seem to be exceptions in all of these and I keep trying a few different varieties each year to find more varieties that can produce in the heat. A sure fire way to not have fruit set in the heat is to let the soil dry out too much on any variety.

Bill

Tormato · June 28, 2013

Not quite a reference, but...

at this temp my tomatoes could use some solace.

http://www.youtube.com/watch?v=hwE5gfZlMZY

Dr. L

ve Apple

**carolyn137** · June 28, 2013

Bill,I'm glad you spoke to the humidity issue since it's very important in addition to temps.

When there's prolonged (don't ask me how long) high humidity the pollen clumps and is much less effective,

Add to that high heat,which denatures the pollen and you've got a double whammy to deal with.

Many years ago Linda Sapp of TGS put me in contact with a hybridizer from Petoseed who was working in FL on the pollen clumping problem but I have yet to see anything more about that in terms of specific varieties

Carolyn

b54red · June 28, 2013

Quote:

Originally Posted by carolyn137

Bill,I'm glad you spoke to the humidity issue since it's very important in addition to temps.

When there's prolonged (don't ask me how long) high humidity the pollen clumps and is much less effective,

Add to that high heat,which denatures the pollen and you've got a double whammy to deal with.

Many years ago Linda Sapp of TGS put me in contact with a hybridizer from Petoseed who was working in FL on the pollen clumping problem but I have yet to see anything more about that in terms of specific varieties

Carolyn

Carolyn, glad to see you back posting. I hope you are feeling much better.

I'm still getting some decent fruit set on some varieties despite near 100% humidity and temps in the 90s; but it has sure slowed down on most varieties and stopped on some. We have been getting one or more thunderstorms every day lately and that gives a little temporary cool down for an hour or so sometimes; but I don't think it has been below the mid 70s even at night for a while now.

Bill

DavidP · June 28, 2013

I'm guessing someone has worked it out to some degree. I read that the majority of tomatoes grown in the US are produced in either California or Florida. For california I bet thats mostly grown in the central valley, have certainly passed truck after truck loaded down with roma type tomatoes (I'm guessing for paste) in the past driving thru there. I think the temp today in Sacramento is north of 100 and probably closer to 110 this weekend. I've also talked with a local farm advisor and they grow tomatoes in the Coachella valley in southern California, could be thats a winter crop but I think the forecast this weekend for the coachella valley is something in the order of 122.

So there must be incentive to grow varieties that set in heat, I know these are more likely the "Valley girl" type determinate that we're unlikely to grow in a home garden but interesting nonetheless.

A hot weekend ahead, forecast for high 120's in Death valley California, I wonder if the world record heat of 134 is in sight.

Sun City Linda · June 28, 2013

I am just south of you David, pretty bad week-end that's for sure. Wonderground has me at 110 Sat and Sunday, about 5 degrees higher than everyone else........hope they are WRONG!

My at risk growing area is full southern exposure, Earthboxes on gravel

Poor Babies. They are absolutely loaded with large fruit but not at breaker yet. I have been out there misting with the hose and plan to keep at it all weekend long.

Stay cool Barb and all the other SoCal inland and desert folks.

RobinB · June 29, 2013

We don't have the humidity (usually). Today got up to 103 with hotter temps in the forecast for Monday/Tuesday. Some plants seem to be setting fruit, but most seem to have stopped doing anything. I like the suggestion of giving them some liquid fertilizer in the afternoon. A little snack.

This evening we got some severe thunderstorms through around 6:00 p.m. It cooled down 22 degrees in about 20 minutes! Two friends that live about 5 miles away from here got 1" hail and winds around 60 MPH. Their gardens were destroyed. I feel so lucky, we just got rain. There was some blossom drop and shredded leaves, but it's not too bad.

Some of my babies haven't been in the ground all that long and they were really suffering in the heat, so this is the solution I threw together today... my Garden Quilt (like Remay) that I use to keep them warm in cold weather. It was too hot this morning to do a pretty job, but I think it it really helped. I ran outside when the storm started and took it all down. I was afraid of high winds! I plan to do something like this each of the coming days, but I'll also get up earlier and try to do a better job!

Sun City Linda · June 29, 2013

LOL! Yes, how would we make do without those old wooden clothes pins. I have old sheets in smaller sections that I clip around the cages.

Worth1 · June 29, 2013

Barb there are no set temps for blossom drop.
As anything else it depends on the variety.

Smaller fruited at my place will set at way over 95 degrees.

Some large fruited play out in the mid 80 degree temps.
I have pretty much gone to planting early determinate tomatoes.

It is a total waste of time to plant anything else.

Worth

Sun City Linda · June 29, 2013

I am trying out determinates this year too. Not only is it too hot here but I am getting too old to deal with those mammoth vines! A tomato called Hanky Red and also Mozart are both absolutely loaded with good size fruit right now. More set than I have ever seen on non cherries.

Salsacharley · June 29, 2013

This past Thursday it was 107 degrees here in Albuquerque, and I had 180 plants I was worried about, so I took my swimming pool cover to set up a shade for them. I almost got heat stroke setting it up but I think the temperature was at least 10 degrees cooler under the shade than outside it.

That night the wind blew about 40 mph and destroyed my shade. Fortunately the temp hasn't gone that high again yet.

I'm starting to get some fruit setting on later varieties like Ananas Noir and Virigina Sweets that makes me hopeful for other even later varieties.

Charley in Albuquerque

June 28, 2013	#1
coronabarb Tomatoville® Recipe Keeper Join Date: Jan 2006 Location: Roseburg, Oregon - zone 7 Posts: 2,821	Temperatures that interfere with pollination I am being questioned on my FB page about the veracity of tomato pollen becoming sterile at high temps. Also, the question of blossom drop with high night temps has come up. I know I have this ingrained in my mind but cannot find a source to back me up. I do not find it in my ultimate authority, Carolyn's book. So, do I remember correctly? Pollen becomes sterile above around 95? How do high night temps interfere with pollination? 75 degrees or so? Is it dependent on how many days the heat occurs? __________________ Corona~Barb Now an Oregon gal

June 28, 2013	#2
amideutch Tomatovillian™ Join Date: Feb 2006 Location: Germany 49°26"N 07°36"E Posts: 5,041	Here are a few references. Ami http://aob.oxfordjournals.org/content/90/5/631.long http://gardening.wsu.edu/library/vege016/vege016.htm http://edis.ifas.ufl.edu/hs1195 __________________ Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘...Holy Crap .....What a ride!'

June 28, 2013	#3
coronabarb Tomatoville® Recipe Keeper Join Date: Jan 2006 Location: Roseburg, Oregon - zone 7 Posts: 2,821	Thank you Ami. Will check those out~ __________________ Corona~Barb Now an Oregon gal

June 28, 2013	#4
coronabarb Tomatoville® Recipe Keeper Join Date: Jan 2006 Location: Roseburg, Oregon - zone 7 Posts: 2,821	These are excellent! Thanks again! :-D __________________ Corona~Barb Now an Oregon gal

June 28, 2013	#6
Tormato Tomatovillian™ Join Date: Feb 2006 Location: MA Posts: 4,959	Not quite a reference, but... at this temp my tomatoes could use some solace. http://www.youtube.com/watch?v=hwE5gfZlMZY Dr. Lve Apple

June 28, 2013	#5
b54red Tomatovillian™ Join Date: Sep 2009 Location: Alabama Posts: 7,068	Anyone who has grown tomatoes in the South knows that the high temps and also the high humidity take a real toll on fruit set. Increasing the amount of water available to the plants and giving them a little boost of a liquid or soluble fertilizer will help in getting some fruit set on many varieties. Some of the hearts,black tomatoes and smaller fruited varieties have the ability to set fruit in higher temps better than most of the pinks and reds especially the large pink beefsteaks. There seem to be exceptions in all of these and I keep trying a few different varieties each year to find more varieties that can produce in the heat. A sure fire way to not have fruit set in the heat is to let the soil dry out too much on any variety. Bill

June 28, 2013	#7
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	Bill,I'm glad you spoke to the humidity issue since it's very important in addition to temps. When there's prolonged (don't ask me how long) high humidity the pollen clumps and is much less effective, Add to that high heat,which denatures the pollen and you've got a double whammy to deal with. Many years ago Linda Sapp of TGS put me in contact with a hybridizer from Petoseed who was working in FL on the pollen clumping problem but I have yet to see anything more about that in terms of specific varieties Carolyn __________________ Carolyn

June 28, 2013	#9
DavidP Tomatovillian™ Join Date: Jun 2011 Location: Riverside, Southern California, USDA 9b, Sunset 19 Posts: 63	I'm guessing someone has worked it out to some degree. I read that the majority of tomatoes grown in the US are produced in either California or Florida. For california I bet thats mostly grown in the central valley, have certainly passed truck after truck loaded down with roma type tomatoes (I'm guessing for paste) in the past driving thru there. I think the temp today in Sacramento is north of 100 and probably closer to 110 this weekend. I've also talked with a local farm advisor and they grow tomatoes in the Coachella valley in southern California, could be thats a winter crop but I think the forecast this weekend for the coachella valley is something in the order of 122. So there must be incentive to grow varieties that set in heat, I know these are more likely the "Valley girl" type determinate that we're unlikely to grow in a home garden but interesting nonetheless. A hot weekend ahead, forecast for high 120's in Death valley California, I wonder if the world record heat of 134 is in sight. Last edited by DavidP; June 28, 2013 at 03:51 PM.

June 28, 2013	#10
Sun City Linda Tomatovillian™ Join Date: Mar 2011 Location: SoCal Inland Posts: 2,705	I am just south of you David, pretty bad week-end that's for sure. Wonderground has me at 110 Sat and Sunday, about 5 degrees higher than everyone else........hope they are WRONG! My at risk growing area is full southern exposure, Earthboxes on gravel Poor Babies. They are absolutely loaded with large fruit but not at breaker yet. I have been out there misting with the hose and plan to keep at it all weekend long. Stay cool Barb and all the other SoCal inland and desert folks.

June 29, 2013	#12
Sun City Linda Tomatovillian™ Join Date: Mar 2011 Location: SoCal Inland Posts: 2,705	LOL! Yes, how would we make do without those old wooden clothes pins. I have old sheets in smaller sections that I clip around the cages.

June 29, 2013	#13
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	Barb there are no set temps for blossom drop. As anything else it depends on the variety. Smaller fruited at my place will set at way over 95 degrees. Some large fruited play out in the mid 80 degree temps. I have pretty much gone to planting early determinate tomatoes. It is a total waste of time to plant anything else. Worth

June 29, 2013	#15
Salsacharley Tomatovillian™ Join Date: May 2013 Location: New Mexico Posts: 2,052	This past Thursday it was 107 degrees here in Albuquerque, and I had 180 plants I was worried about, so I took my swimming pool cover to set up a shade for them. I almost got heat stroke setting it up but I think the temperature was at least 10 degrees cooler under the shade than outside it. That night the wind blew about 40 mph and destroyed my shade. Fortunately the temp hasn't gone that high again yet. I'm starting to get some fruit setting on later varieties like Ananas Noir and Virigina Sweets that makes me hopeful for other even later varieties. Charley in Albuquerque