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hendi_alex
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Tomatoes: heat, humidity, disease

I'm beginning to think that the presence of disease in the soil and air is not really the main cause of crop loss in mid to late summer. I'm thinking that the real culprit is the over 90 degree days with muggy mid 70 degree nights. The disease becomes especially rampant when these temperatures combine with July afternoon thundershowers.

This year 100% of my tomato plants died or just showed modest signs of life by mid to late July. I had started some cuttings as well as a few seedlings which survived the period nicely. It seems that young plants which are vigorously growing, especially when grown in synthetic soil, are not affected much by the disease. These plants were held in reserve until the temperatures moderated in mid August. They were then placed in the same containers, with the same soil which had been used to grow the earlier diseased tomatoes. With the cooler temperatures, most between 70 nightime to 90 daytime, the plants have shown almost no signs of disease. And while most have some diseased leaves near the bottom, the top growth is vigorous and of healthy shape and color.

My biggest mistake this year is in only starting replacement plants through about mid May. Next year I'll continue to make fresh cuttings and planting new seedlings through mid to late June. That way, perhaps we will avoid the approximate 4 week period that we experienced without tomatoes this year. This is the first time in over ten years that we have had a break in our tomato stream during the summer. The problem was most likely caused by the extremely wet season with rain two or three days per week through much of June and July.

Here are a couple of the Fall replacement plants which should be ripening soon.

[img]https://farm9.staticflickr.com/8034/7999615029_07563a70a7_b.jpg[/img]

[img]https://farm9.staticflickr.com/8304/7999618398_c51d22e9e0_b.jpg[/img]

DoubleDogFarm
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Interesting experiment Alex, plunging healthy plants into diseased ridden soil.

I wholeheartedly believe that healthy soil makes healthy plants. Not sure I can believe healthy plants can restrain unhealthy soil. Maybe it's just a race.

Keep use posted.

Eric

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hendi_alex
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I'm thinking that the disease is everywhere. Even when planted in sterile soil in large above the ground containers, the plants become infected and start to die in mid July to mid August. As I say it doesn't appear to be the presence of the disease so much as the presence of the conditions under which the disease tends to thrive. If that is the case, then planting a constant succession of tomato plants every few weeks from April through September will likely result in an unbroken stream of ripe tomatoes throughout the season. Planting in fresh soil would likely be helpful, but at this point doesn't seem particularly necessary. As long as it works and gives a high quality result, I'll continue to recycle the soil.

So far so good on the experiment. The tomatoes are obviously affected by the disease, but with only slightly more moderate temperatures, the plants are able to grow vigorously and continue to set fruit.

BTW, all of the cuttings were made from the upper healthy looking branches from heavily diseased plants. They showed not signs of the disease until just recently.

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hendi_alex
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So it is now the end of September and my theory of the effect of temperature on disease susceptibility is holding up so far. There are still signs of disease on lower branches, but the disease is moving very slowly as to not be a problem and new growth is sharply outdistancing any problems with disease. We have been harvesting a trickle of tomatoes for a week or longer, and if frost holds off for another 3-4 weeks we should get a nice crop before the vines are killed. I may even consider moving a few of the large container plants into the greenhouse, to give the tomatoes a little more time to ripen.

Here are a few photos. The plants are growing vigorously, setting lots of fruit, and showing only modest signs of summer blight.

[img]https://farm9.staticflickr.com/8316/8035760728_fd90cd558d_o.jpg[/img]

[img]https://farm9.staticflickr.com/8453/8035760838_521d542a6d_o.jpg[/img]

[img]https://farm9.staticflickr.com/8042/8035760926_139bdcd49e_o.jpg[/img]

[img]https://farm9.staticflickr.com/8319/8035759933_1948a0fc83_o.jpg[/img]

[img]https://farm9.staticflickr.com/8460/8035760029_5827666a8d_o.jpg[/img]

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lakngulf
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Those are some healthy plants for this time of the year in the South. I had similar cases of "play out" with my vines, but I did do successive plantings and have a few still with small tomatoes. Matter of fact, we are set for a round of BLTs and fried okra tommorrow night.

As I have posted, this past year I tried several varieties with mixed results. Basically, I took a page out of your planting guide book and just planted a bunch of tomatoes, knowing some would die.

Good luck with your experiment, maybe frost will be late, and/or you could cover a couple of plants a night or two.

Dillbert
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hendi_alex

I think your basic idea is absolutely spot on.

tomatoes have bacterial type diseases and fungal type diseases.

one could think a particularly well advantaged soil could contain a famous "soil web" of one sort or another that would decimate the spores/traces of bacterial/fungal diseases that take up soil residence. if, of course, one believes the "soil borne" theory of the last 70 years or so. but that also implies a "soil web" bug that has specifically evolved to eat those specific nasties. frankly, I don't hold a lot of hope for that scenario.

...........can you tell I'm trying to do a politically correct "dance around stuff" here. . .

when "conditions" are right-to-perfect the diseases just explode.
some years you win, some years you lose.

and, I'd also agree there's few spots of gardening dirt where some-to-lots of the disease traces/carriers aren't found . . .

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hendi_alex
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Next year I'm going to rig a cheap fan to blow a constant stream of air on two or three plants. I'm wondering if the constant movement of air, combined with heavy pruning of interior branches will discourage the disease from progressing so rapidly in the 6-8 hottest weeks of summer. I'm also thinking of using some shade cloth on those and a few other plants starting when the night temperatures move above the 60's.

Dillbert
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iffin' I was forced to guess at my best "defense result" I'd have to say "it's the mulch"

typically I use "fresh off the lawn" grass clippings same day as planting - thick - like 4-6 inches, pulled back until the clippings "cool off" a bit.

and keep it thick.
and prune off the lower branches.

this year due to the dry conditions I did not have a sufficiency of grass clippings, so I chopped up some straw at planting / set out time. I later added clippings most everywhere except the end of one row - dingie-dongie oversight, I suppose - and the straw eventually got a bit thin down there. curiously, that is _exactly_ where late blight took hold this year - right there at that end where the mulch got thin.

I typically grow a mix of heirloom and hybrids with various 'resistances' - frankly don't often lose too much to blights/wilts - but mulch mulch mulch is my mantra.

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hendi_alex
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Fall experiment continues. Disease continues to move up the plants, but at a slow pace. Plants continue to produce fruit fast enough to stay ahead of our needs. This year's experiment would indicate that tomato disease is not much of a problem once the temperature and humidity drop in late summer. You will note that disease has taken most of the growth from the tomatoes in lower branches, but top growth is barely affected and new fruit is continually setting.

Today's inventory of harvested tomatoes:

[img]https://farm9.staticflickr.com/8464/8113952610_6f0c18bc89_o.jpg[/img]

Four of six plants:

[img]https://farm9.staticflickr.com/8470/8113944835_b1723e491c_o.jpg[/img]

[img]https://farm9.staticflickr.com/8193/8113944985_40dbf44a20_o.jpg[/img]

[img]https://farm9.staticflickr.com/8043/8113944733_6fbe513fe2_o.jpg[/img]

[img]https://farm9.staticflickr.com/8469/8113953110_8e9d051f89_o.jpg[/img]

Looks like we will have fresh tomatoes until late November or early December! That will be interesting, as I will start next year's earliest transplants in mid December. Those may possibly get planted before we have eaten the last of this year's crop.

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lakngulf
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hendi_alex wrote:Looks like we will have fresh tomatoes until late November or early December! That will be interesting, as I will start next year's earliest transplants in mid December. Those may possibly get planted before we have eaten the last of this year's crop.
How do you handle the frost and cold temps?

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ReptileAddiction
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DO you grow determinate or inderminate in containers? I am planning next years tomatos...

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hendi_alex
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I mostly grow indeterminate tomatoes, though do plant a few Marion in the ground.

Our first frost doesn't usually come until the third week in November. This year I'll probably cut the vines near the soil level will hang the vines in the greenhouse and allow the tomatoes to continue ripening on the vines. Those tomatoes will likely take us into the first or second week in December. Our earliest seedlings are grown in the greenhouse until mid January. After that the plants are moved outside on sunny days that are over 60 degrees. Sometimes they are moved outside in portable cold frames on sunny days that are above 50 degrees. The 6-8 earliest plants are always moved back inside overnight any time that the night time low drops below the low 40's.

Here in central S.C. January and February usually gives lots of sunny days with temperatures in the 50's and 60's. Plants that are taken outside at every opportunity tend to grow strong and give very early harvests.

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lakngulf
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hendi_alex wrote:Here in central S.C. January and February usually gives lots of sunny days with temperatures in the 50's and 60's. Plants that are taken outside at every opportunity tend to grow strong and give very early harvests.
We get about the same down here in central Alabama. My problem is I do not have a good method to get the pots in and out of greenhouse. I am working on that.

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hendi_alex
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My earliest batch only consists of 6-8 plants, so moving them in and out is not real problem. Actually by mid January I usually move the plants into our house. Eight plants don't have much of a footprint until March or so when the plants get potted into 3 gallon nursery containers. It only takes about two or three minutes to move the eight plants in one direction or the other.

Things get pretty involved in February or March after the second and third batch of seedlings start getting up potted to one gallon containers. At that point, perhaps three dozen or more plants are being moved back and forth when the nightly temperatures drop. Last year was great, as most days allowed us to leave the plants outside in cold frames with lows in the mid to upper 40's. This year won't likely be quite so warm. If that is the case, then there will be lots of transporting during early to mid spring.



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