Tomatoes grow in 90 degree weather?

linzelu100 · May 13, 2014

It's been in the 90's for a week and a half in my muggy little corner of virginia- per my temperature gauge. HOT HOT HOT and very sunny. I read somewhere that tomatoes "shutdown" above 90 degrees. Is there truth to this? My plants are healthy looking and I have been watering if they look wilty, but its so hot. Will I not get any tomatoes because of this extreme heat? Its been 99, 98, 97, 95...94 today. Usually around this time its rainy and cool.

**carolyn137** · May 14, 2014

Quote:

Originally Posted by linzelu100

It's been in the 90's for a week and a half in my muggy little corner of virginia- per my temperature gauge. HOT HOT HOT and very sunny. I read somewhere that tomatoes "shutdown" above 90 degrees. Is there truth to this? My plants are healthy looking and I have been watering if they look wilty, but its so hot. Will I not get any tomatoes because of this extreme heat? Its been 99, 98, 97, 95...94 today. Usually around this time its rainy and cool.

Tomatoes grow quite well above 90 but the chances of blossoms setting fruit is low to nothing. And that's b'c sustained temps over about 85 or so denatures the pollen making it not effective. It gets even worse when there;s high humidtiy b'c that causes clumping of pollen making it not effective.

So those who live where there are usually high sustained temps, PLUS high humidity get a double whammy, as it were.

Which is why most folks who live in those areas start their plants early to put out so they can set fruit before those conditions set in/

One wouldn't expect such high temps n VA in the middle of May, but it has happened before and will happen again. No different really, in my area of finding snowstorms in late MAy, which has happend before and will happen again.

The weather, she changes.

Carolyn

b54red · May 14, 2014

Sounds like you are having the same trouble as most in the south this year. Had to wait later than normal to set them out then it went from almost too cold to hot overnight. I was 5 weeks behind my average starting date and still risked frost yet it turned really hot before the plants ever started to bloom. Don't let your plants wilt if they are blooming or you will have very little fruit set. Over the years I noticed that when tomatoes wilted or the soil got too dry during the heavy blooming stage that the stress would cause blooms to drop off shortly afterwards without setting fruit. If a good soil moisture level is maintained then the plants have a much better chance to set in the heat. It also helps if that soil is heavily mulched to keep it cooler as well as keep soil moisture more even. Fruit set is rarely normal in very hot weather so keep them watered and keep your fingers crossed. Once you get a good fruit set you can return to normal watering.

Bill

Cole_Robbie · May 17, 2014

Quote:

Originally Posted by carolyn137

sustained temps over about 85 or so denatures the pollen making it not effective. It gets even worse when there;s high humidtiy b'c that causes clumping of pollen making it not effective.

I didn't know that about high humidity. Two years ago, my weather was hot and unusually dry. I learned that very low humidity causes pollen dessication - it dries out too fast. Even pumpkins wouldn't set. I had big green vines because I irrigated, but they produced nothing.

Worth1 · May 17, 2014

Quote:

Originally Posted by Cole_Robbie

I didn't know that about high humidity. Two years ago, my weather was hot and unusually dry. I learned that very low humidity causes pollen dessication - it dries out too fast. Even pumpkins wouldn't set. I had big green vines because I irrigated, but they produced nothing.

Coming from a man of your vast experience and knowledge about plants I find this shocking.

Worth

Tracydr · May 18, 2014

Quote:

Originally Posted by Cole_Robbie

I didn't know that about high humidity. Two years ago, my weather was hot and unusually dry. I learned that very low humidity causes pollen dessication - it dries out too fast. Even pumpkins wouldn't set. I had big green vines because I irrigated, but they produced nothing.

Yes, I deal with that most years. Our spring weather is often in the 90s with 5% or less humidity. Our dewpoint is around 35-40 F. I've never seen dew here!

**carolyn137** · May 18, 2014

Quote:

Originally Posted by Cole_Robbie

I didn't know that about high humidity. Two years ago, my weather was hot and unusually dry. I learned that very low humidity causes pollen dessication - it dries out too fast. Even pumpkins wouldn't set. I had big green vines because I irrigated, but they produced nothing.

Here's a link about tomato pollen clumping

https://www.google.com/#q=tomato+pol...mping+humidity

And I think it was in those two links from 2010 in the Tomatoville heading that I described how I found out about it via the Petoseed hybridizer based in FL.

Carolyn

feldon30 · May 14, 2014

Temperatures have been about 15 degrees above normal around here. We just need a few days to dip into the 70's with overnights in the high 50's to low 60's and then you'll see some fruit setting.

Stvrob · May 14, 2014

Here in NE Florida, last year I had tons of fruit set before it got hot, but I'm thinking I'm about 3 weeks later than last year because of the cold spring. The past 2 weeks has been quite warm, about 90, but not the high humidity summer-like weather, rather a dryer, breezy hot. The plants are using tons of water, and I'm worried Im not getting much fruit set.

Redbaron · May 14, 2014

Tomatoes can set fruit in hot weather, but you'll need all the help you can get from beneficial insects to do it. That's why I plant lots of companion plants around my tomatoes like marigolds basil and even a few huge sunflowers scattered here and there. I plant my rows north to south and so it the hottest part of the day around noon, the sunflowers provide some shade. But early in the day and late evening the sun strikes the plants well enough for full sun. Swarms of wild sweat bees by the thousands can be found around the plants especially in the early AM. Later on other insects can be found buzzing around the basil and marigolds.

I guess you could call this anecdotal evidence, but I get fruit set when all my neighbors have shut down due to temps.

Stvrob · May 14, 2014

I have an "electric bumblebee" (My daughters electric toothbush), which I'll use every other day or so.

parah · May 16, 2014

Quote:

Originally Posted by Stvrob

I have an "electric bumblebee" (My daughters electric toothbush), which I'll use every other day or so.

The "electric bumblebee" definitely helps in my garden and it gives me another reason to get out there and inspect the plants up close on a regular basis.

Bonus: wandering around with an electric toothbrush gives the neighbors something to gossip about!

travis · May 14, 2014

Some varieties have the ability to set fruit at temperatures above 92*F, and some do not. Humidity also is a variable factor depending on the variety.

Have faith, cooler weather is headed your way tomorrow. It's dropped 20 degrees out here in the Ohio River Valley from the weekend until today.

linzelu100 · May 14, 2014

Thanks all. I haven't gotten any blossoms yet. Which surprised me. What B54red stated is very true here...it was too cold, so I waited to plant out and then BOOM Hot Hot. I usually have some flowers by now. I was thinking maybe it was the heat.

Geeze...if its this hot now, what is the summer going to be like?!

creister · May 17, 2014

I don't have your humidity, but I have noticed that if we get night temps in the 60's, then fruit set seems to do ok even with high daytime temps. I know livestock fair much better with nighttime cooling, a seasonal factor used to determine nutrition requirements for livestock. I believe that to be true for tomato. Just an observation, no formal science involved.

May 13, 2014	#1
linzelu100 Tomatovillian™ Join Date: Apr 2013 Location: Virginia Posts: 447	Tomatoes grow in 90 degree weather? It's been in the 90's for a week and a half in my muggy little corner of virginia- per my temperature gauge. HOT HOT HOT and very sunny. I read somewhere that tomatoes "shutdown" above 90 degrees. Is there truth to this? My plants are healthy looking and I have been watering if they look wilty, but its so hot. Will I not get any tomatoes because of this extreme heat? Its been 99, 98, 97, 95...94 today. Usually around this time its rainy and cool. __________________ Lindsey

May 14, 2014	#8
feldon30 Tomatovillian™ Join Date: May 2006 Location: Rock Hill, SC Posts: 5,346	Temperatures have been about 15 degrees above normal around here. We just need a few days to dip into the 70's with overnights in the high 50's to low 60's and then you'll see some fruit setting. __________________ [SIZE="3"]I've relaunched my gardening website -- [B]TheUnconventionalTomato.com[/B][/SIZE] * [I][SIZE="1"]*I'm not allowed to post weblinks so you'll have to copy-paste it manually.[/SIZE][/I]

May 14, 2014	#10
Redbaron Tomatovillian™ Join Date: Sep 2012 Location: Oklahoma Posts: 4,488	Tomatoes can set fruit in hot weather, but you'll need all the help you can get from beneficial insects to do it. That's why I plant lots of companion plants around my tomatoes like marigolds basil and even a few huge sunflowers scattered here and there. I plant my rows north to south and so it the hottest part of the day around noon, the sunflowers provide some shade. But early in the day and late evening the sun strikes the plants well enough for full sun. Swarms of wild sweat bees by the thousands can be found around the plants especially in the early AM. Later on other insects can be found buzzing around the basil and marigolds. I guess you could call this anecdotal evidence, but I get fruit set when all my neighbors have shut down due to temps. __________________ Scott AKA The Redbaron "Permaculture is a philosophy of working with, rather than against nature; of protracted & thoughtful observation rather than protracted & thoughtless labour; & of looking at plants & animals in all their functions, rather than treating any area as a single-product system." Bill Mollison co-founder of permaculture

May 14, 2014	#14
linzelu100 Tomatovillian™ Join Date: Apr 2013 Location: Virginia Posts: 447	Thanks all. I haven't gotten any blossoms yet. Which surprised me. What B54red stated is very true here...it was too cold, so I waited to plant out and then BOOM Hot Hot. I usually have some flowers by now. I was thinking maybe it was the heat. Geeze...if its this hot now, what is the summer going to be like?! __________________ Lindsey

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May 14, 2014	#3
b54red Tomatovillian™ Join Date: Sep 2009 Location: Alabama Posts: 7,068	Sounds like you are having the same trouble as most in the south this year. Had to wait later than normal to set them out then it went from almost too cold to hot overnight. I was 5 weeks behind my average starting date and still risked frost yet it turned really hot before the plants ever started to bloom. Don't let your plants wilt if they are blooming or you will have very little fruit set. Over the years I noticed that when tomatoes wilted or the soil got too dry during the heavy blooming stage that the stress would cause blooms to drop off shortly afterwards without setting fruit. If a good soil moisture level is maintained then the plants have a much better chance to set in the heat. It also helps if that soil is heavily mulched to keep it cooler as well as keep soil moisture more even. Fruit set is rarely normal in very hot weather so keep them watered and keep your fingers crossed. Once you get a good fruit set you can return to normal watering. Bill

May 14, 2014	#9
Stvrob Tomatovillian™ Join Date: Jan 2013 Location: Jacksonville, FL Posts: 1,413	Here in NE Florida, last year I had tons of fruit set before it got hot, but I'm thinking I'm about 3 weeks later than last year because of the cold spring. The past 2 weeks has been quite warm, about 90, but not the high humidity summer-like weather, rather a dryer, breezy hot. The plants are using tons of water, and I'm worried Im not getting much fruit set.

May 14, 2014	#13
travis Tomatovillian™ Join Date: Jan 2006 Location: Evansville, IN Posts: 2,984	Some varieties have the ability to set fruit at temperatures above 92*F, and some do not. Humidity also is a variable factor depending on the variety. Have faith, cooler weather is headed your way tomorrow. It's dropped 20 degrees out here in the Ohio River Valley from the weekend until today.

May 17, 2014	#15
creister Tomatovillian™ Join Date: Feb 2006 Location: Abilene, TX zone 7 Posts: 1,478	I don't have your humidity, but I have noticed that if we get night temps in the 60's, then fruit set seems to do ok even with high daytime temps. I know livestock fair much better with nighttime cooling, a seasonal factor used to determine nutrition requirements for livestock. I believe that to be true for tomato. Just an observation, no formal science involved.