Effect of heat and humidity on tomatoes

[JohnMich]

Hi All!

Have started growing tomatoes in SWC using a gadget from Bunnings that fits into bottom of large pots. Anyway all was going well until we just had a burst of really hot weather 27-33C (about 84-93F) and high humidity for 10 days but with drops down to only 20C at night.

Bush tomatoes that were going along very nicely now look like they've been hit with a blow torch. They are getting full sun from about 8 a.m. to 4.30 p.m. Is the sun killing them?
Have a look at pictures of same plant separated by about 3 weeks. After the early pics were taken the plant seemed to stall and there was little growth or ripening until about 10 days ago then it started to ripen and then turned 'yuck'!
Fertiliser has been Seasol when transplanted for stress relief, Powerfeed and Thrive Tomato Concentrate since.

My suspicion is that the plants are getting too much sun and wet heat.

Your comments would be appreciated

Regards, John

PS: For Aussies we live on Gold Coast and we are closest to Zone 11 US

[amideutch]

John, do you actually have a reservoir in the bottom of your SWC or is the gadget just watering the plant from the bottom of the container. It looks like shade cloth may be in order and the plant may not be getting enough water in the heat with your current system. Ami

[Salty_Dog]

Hey John,

We just had a very similar stretch of hot humid weather here in Victoria (9 days above 35 degree C)
I have 4 Tomatoes in SWC's and they all flourished in the heat... they just loved it.
I might point out, they were watered morning and night, and top watered a little as well as having the reservoir filled.

I think that is key... when the weather is hot and unbarable, you just have to keep the water up to your container plants.

I have always adjusted my watering in times of extremely high heat; all i find is the plants are tired and wilted come evening (just as we would be after a day in the sun) but come the morning they are lush, green and standing tall.

Some Seaweed or Seasol (I see you are using some) may also help your plants withstand high temps and drought conditions too.

My plants get full sun from 8am to 4.30pm also... from what i have noticed with my own plants over this last hot spell..... If the plants can access the water, they will... and as long as the water remains available, they will cope.

Even my plants in little 8 inch pots survived.

Sorry to hear your plants have suffered, hope they can fight back.

BTW, i have one of those old school SWC in the fake Terra Cotta colored plastic, personally i don't trust it and top water it every time.
It just doesn't wick like the home made SWC's do. I look at the water in the base as a back up, but i'd hardly trust it.

[JohnMich]

Ami, the gadget is about 300mm across and like the bottom half of a flying saucer. The flat top has holes and a well - see pic split in two and joined. Very clever actually and working extremely well with ferns in hanging baskets under the patio and getting light through translucent poly panels.

But from what you and Salty are saying I think that the answer lies with a bit of shading at high noon and in afternoon and a LOT more water. Like heaps more.

Salty, in fact I think that your tunnel house may be taking some of the fierceness out of the sun and don't forget we are about 1500 kms closer to the equator than you so the sun tends to come down at an angle much closer to the vertical.

I think between you blokes you have come up with the solution.

Thanks for the speedy responses.

By the way Salty it looks as if your bucket SWCs are using a ring formed from a bucket lid to hold the plastic tight on top - is that correct? Guess what I will be starting on tomorrow. They will look remarkable like your model!

Many thanks, John

[Blueaussi]

Originally Posted by Salty_Dog

BTW, i have one of those old school SWC in the fake Terra Cotta colored plastic, personally i don't trust it and top water it every time.
It just doesn't wick like the home made SWC's do. I look at the water in the base as a back up, but i'd hardly trust it.

You know, someone gave me several of those 4 or 5 years ago, and I felt the same way you did. I didn't have vegetables in them, I had flowers and a few herbs; but I came to the same conclusion, that they don't wick well. I gave up self watering containers as a bad deal until I read about the earthtainers. I'm going to give a couple of them a go next season.

[Salty_Dog]

Yep that is the exact one John. The very same unit i have.
And all my plants are out of the hot house now, have been for at least 5 weeks.
The SWC did not seem to like it in the hot house, in fact, almost anything in a container didn't like it and still remains to do so.

As for the angle of the sun, yeah i know what you are saying, i just got back from Airlie Beach. A lot more humid but the sun doesn't seem to pack the same punch as down here.
I can go all day without sunscreen up there and not burn, you can't do that down here, 3 hours and you're burnt.
I have a lot of Queensland friends that complain of the suns strength when visiting here.

But back to your problem, i'd say if you were relying on the wicking principle alone and not top watering, or at least not watering every day... that would be your problem.

[JohnMich]

I wish I had talked to you blokes before the season started but it's OK up here in 'cool' Quensland (refer Salty Dog's remarks) we can grow tomatoes all year round - out in the open.

I've made the mistake of seriously under-estimating watering needs. But I can cure that.

Thanks for your contribution BlueAussi - and your atavar looks like an iconic Aussie canine.

Incidentally SD I think that the pics of an SWC I was looking at wasn't one of yours but very akin to it - where can I find the original, please?

Regards, John

[JohnMich]

Salty, you old dog, like all Victorians you love your state but -
(a) because of your attempt to lure our tourists away, and,
(b) because some of what you said about sun intensity cannot go unchallenged I offer the following -

It may be that you Victorians have very thick skins but suggesting that mere mortals can walk around all day at Airlie Beach and not get burnt but 3 hours at Lorne, Vic, would be too much is not real clever.

We Banana-benders are telling everyone to slip-slop-slap - hats, clothes and sun screen.

Australia unfortunately has the highest rate of skin cancer in the world and the further one goes North in australia the higher the rate of skin cancer because of the higher intensity of UVs.

Brisbane, at the very southern edge of the great state of Queensland is 10 degrees of latitude north of Melbourne ( a city near Lorne) - and in sun terms that is a long way north. Victoria is in the cool temperate zone. Brisbane - a long way south of Airlie is in the sub-tropics!

So folks if you come to Australia remember the chart attached sourced from
NSW Cancer Council and Anti-Cancer Council Victoria

and use a lot of sun screen even when you are in cool Victoria.

And Salty you may have been kidding but don't forget not everyone understand Oz ironic humour and may have believed you, although obviously any Aussie who had ventured out of Victoria wouldn't

Regards, John - and keep stirring mate!

[Aussiemark]

Hi JohnMich,

I agree with Salty in regards to sun intensity in QLD. Yeah it's hotter and more humid, but in my personal experience the sun stings more in the South.

The WA sun is the most potent I have experienced and it, Perth and surrounding area, is well south of QLD, but the intensity of the sun is much stronger in my experience (even if the weather is cooler).

Just my personal observation.

Mark

[Salty_Dog]

Originally Posted by JohnMich

Salty, you old dog, like all Victorians you love your state but -
(a) because of your attempt to lure our tourists away, and,
(b) because some of what you said about sun intensity cannot go unchallenged I offer the following -

It may be that you Victorians have very thick skins but suggesting that mere mortals can walk around all day at Airlie Beach and not get burnt but 3 hours at Lorne, Vic, would be too much is not real clever.

We Banana-benders are telling everyone to slip-slop-slap - hats, clothes and sun screen.

Australia unfortunately has the highest rate of skin cancer in the world and the further one goes North in australia the higher the rate of skin cancer because of the higher intensity of UVs.

Brisbane, at the very southern edge of the great state of Queensland is 10 degrees of latitude north of Melbourne ( a city near Lorne) - and in sun terms that is a long way north. Victoria is in the cool temperate zone. Brisbane - a long way south of Airlie is in the sub-tropics!

So folks if you come to Australia remember the chart attached sourced from
NSW Cancer Council and Anti-Cancer Council Victoria

and use a lot of sun screen even when you are in cool Victoria.

And Salty you may have been kidding but don't forget not everyone understand Oz ironic humour and may have believed you although obviously any Aussie who had ventured out of Victoria wouldn't

Regards, John - and keep stirring mate!

To be honest John, the thing I like most about this site is the non trolling and friendly nature of people... plus the way threads stay on topic and no personal remarks get made towards other members trying to help out.

I see not all members are like this.
Good Luck with your tomatoes.

P.S. Funny how people categorise people, not realising they grew up in Burleigh Heads for 20 years before moving south.

[JohnMich]

OK Salty and Auusiemark (another Victorian I note)

I was responding to this piece of nonsense in which you read what I said and got it exactly the wrong way round.

Originally Posted by Salty_Dog

As for the angle of the sun, yeah i know what you are saying, i just got back from Airlie Beach. A lot more humid but the sun doesn't seem to pack the same punch as down here.
I can go all day without sunscreen up there and not burn, you can't do that down here, 3 hours and you're burnt.
I have a lot of Queensland friends that complain of the suns strength when visiting here.

Fact: UV causes sunburn
Fact: See attachment re: intensity of UV rays across Australia
Opinion: Sun in Lorne, south of Melbourne, is more intense than say Airlie Beach about halfway between Mackay and Townsville, Queensland - and blow me Perth has got into the act with just about the same relevance - have a look at the chart it's not my opinion it comes from the Australian Bureau of Meteorology

I tried to put a bit of humour into what I was saying just in case I had misunderstood you.

My justification for saying what I said was that the opinion you were expressing flew in the face of the facts. You could have put some innocent in danger of getting very sick indeed.

I don't care where you have lived Salty, as it happens I live 7 kms from Burleigh and have done for 16 years - so what? It doesn't change the facts - and neither does it categorise you as anything but an ex-Queenslander.

It was very much on topic - it was you who came up with your opinion about sun strength in Lorne being greater than Queensland. Look at the heading of the thread. And your wrong opinion impacts on discussion of tomatoes as much as human beings

As for your reference to me making personal remarks your attempt to do just that is so silly.

John

[Aussiemark]

John,

Just posting my personal observations. The chart is good information, thanks for posting it.

Perth has the most hours of sunshine per year of any Australian capital city so this could play a roll in my personal observations and would not fit into a clear sky at noon UV index, which is good information but pretty specific. ie Perth has a lot more clear sky at noon than Brisbane does, so more UV in total.

When you then add in heat and humidity (as per your original post), not the same as sunshine or UV, you have a number of different factors that can influence people and plants.

Interesting to get different opinions.

Mark

[JohnMich]

Thanks Mark, you make sense and I appreciate that

John

[JohnMich]

Me again Mark. You seem interested in facts so clicking on this
>>>>> http://tinyurl.com/yzvt6u9 will take you to a Bureau of Meteorology site where my last chart came from but which also includes sunshine duration, intensity measured in megajoules, thunder and lightning. All interesting stuff. Also note that month by month figures are available as well as annual.

This discussion has resulted in a good result for me, I've learnt (from Salty and AmiDeutch) that there is such a thing as too much sun for tomatoes but more importantly that only the home-made SWCs with BIG reservoirs can really cope with OZ conditions
Regards, John

[creister]

You are correct about too much sun. One summer, about mid July, I planted out some fall transplants in SWC. I ended up using a 30% shade cloth until they became larger and sun intensity lessened.