Visiting Germany I saw incredible tomatoes growing within thick high hedges. When I questioned lack of sun I was told Germans consider Tomatoes shade plants. This year I am doing an experiment on my west facing Lanai in Southwest Fl. I have 20 plants from seed in large pots - they get Sun only when the sun passes over our building (about 1:30 to 6:30 or 5 hrs). 10 get sun through a dark screen which is cuts down the sun quite a bit. The other 10 get it direct. Results so far: All are thriving even with the 4-5 hrs sun they get. Those that get their sun through the screen have blossoms (35 so fasr), those with direct sun have no blossoms but the plants look great. The ones that get direct sun wilt during the direct sun period, the others do not. Within 2 hrs past direct sun the wilted plants recover. All are watered the same and I use a soil moisture meter to follow that (ususally every 3 days). I will continue the expt a bit longer but will likely get my 10 Sunnies behind a screen.

This is an old thread, but since I came across it while looking for something else, thought I'd put my 2 cents in for the archive. The OP's wilt problem looks to me exactly like Bacterial Wilt - green, badly-wilted leaves happening overnight with maturing fruit already on the plant. I've been struggling with it two years in a row. Online, most sources say nothing much you can do about it except pull the plant, plant elsewhere next year, plant resistant varieties, etc. Personally, I find that advice hard to live with for a variety of reasons, so I've been experimenting. What I've learned so far is that: 1)watering the soil makes things worse - the disease affects water transport in the stems so the water never makes it to the leaves, and meanwhile, the water in the soil seems to help the bacteria thrive. When I let the soil dry out some, the most badly affected stems start to die off, but the less affected stems seem okay, especially with some foliar feeding. I think part of the key to dealing with Bacterial Wilt is to allow the soil to be fairly dry and foliar feed the healthier parts of the plant when they need water. 2)Foliar feeding with milk/water mixtures (I've sometimes added some epsom salt, molasses, some fish emulsion), helps the less affected stems to strengthen up in relation to the disease. Using the above two ideas, as of yesterday, my plants were looking greatly improved. However, it's now pouring rain, so I may be back at square one by tomorrow!

due to fusarium wilt or is it too much water Of those two choices the odds are far more likely to be too much water than FW. Especially given your weather of late and the presence of moldy soil. But there are many other possibilities as well and your local county extension office may be able to help you diagnose the real problem. If that is the case, there is little you can do except hope that the weather improves and the soil begins to dry out. Weather and especially excess rain, is something many of us have had to deal with this year. Clay soil is notorious for retaining water tho one usually doesn't associate clay soil with Florida. ;) Assuming that is what you have then you may have better luck with large containers or raised beds as they drain much faster. Good luck. Dave

Duplicate post. See http://forums.gardenweb.com/discussions/3962635/sudden-wilting-in-cherry-tomato-and-other-tomato-plant?n=1