I was so proud of my tomato plants (grown from seeds), but now I'm worried that they have died...
Instead of having a usual French summer (with 30 C at least and dry weather) it is raining a lot and it is cold (18-20 C). Up to now (until last week or so) I was not worried because the tomatoes did well, a lot of flowers and some fruits were appearing. Then suddenly the stems became black, not only black dots and yellow leaves as described here but real areas. In addition the leaves have dried out.
Is there anything I can do? If not, what could I have done to avoid this situation beforehand? ("In gardening there is always a next year")
Here are some pictures (click to enlarge).