Lower N in your amendments-Check watering schedule. Click on FAQ at top of this page, Look at 'BER". Knowing your zone and growing method would help you get better info. Good Luck Bill

Yeah watering has a lot to do with it. Too much water will rot your crops for sure.

Here is a link that might be useful: Home Gardening

What kind of "rot"? That can mean many different things. If you mean they get a large black area on the bottom where the blossom was that is called Blossom End Rot or BER as mentioned above.

If that is the case it can be fixed and the FAQ here plus a search of the forum using "BER' will get you lots of info on it. But if you are talking about some sort of total fruit rot with accompanying diseased plants it is another matter. Could you provide more details and description of the rot and the condition of the plants?

Dave

Here is a link that might be useful: BER FAQ

Maybe:

Late Blight. Cause by a fungus that is favored by wet weather. Spores travel and can cause plants and fruits to suddenly rot.

Avoid crowding. Remove and destroy all infected plants.

In wet warm weather any crack or little worm hole will develop rot. Some varieties of tomatoes have thin skin or more cracks or taste better to the bugs and will rot easier than others. I liked the taste of Black from Tula better but Celebrity was less likely to rot. I usually don't get over 9 inches in one storm system so I am not expecting a return of last year's weather.

Hmmm - was hoping we'd get a reply here from the OP with more details.

Gardening zone/location? Are these tomatoes growing now or are we talking about last year? Late blight kills the plants, not the tomatoes, so were these plants ok in appearance? Maybe the fruit was just left too long on the vines? Picking at blush solves that problem.

Otherwise this is all just guess work and of little value in solving the problem.

Dave

Thanks for all the replies, central FL, zone 9 I believe, they go from green to yellow and moldy very quickly with some giving the appearance of starting to ripen only to rot on the vine, last years crop in the summer, how much water is too much water.Soil is beautiful and very loamy for this area not sandy which is the norm. EW