My big beef have much smaller as the season progress. I do not feed my tomatoes after bloom set and blight has hit them pretty bad.. there is still several tomatoes on the vines that are much smaller but usable. early girl still producing but also smaller. I have planted big beef the last 2 yrs and the are my main crop and will continue to replace big boy and whoppers that i use in past

I like the Big Beef also, and all of my tomatoes get smaller toward the end of summer.

This sort of behavior is typical of tomato plants late in the growing season. The plants are now tired and worn out, having expended a great deal of energy the last few months while growing and producing/ripening fruit. It is perfectly normal for the fruit to get smaller as the season goes on. It happens to my plants every year, and I just don't worry about it. By the time the plants are producing significantly smaller fruit, we've just about overdosed on fresh tomatoes anyhow and I've already canned, frozen and dehydrated more than enough tomatoes to get us through the non-tomato-growing season.

The decrease in fruit size is one reason why lots of gardeners in the south will plant a second round of tomato plants in mid- through late-summer (the timing depends on how far south they are) for a fall crop. Fresh, new plants will have more vigor and will produce larger fruit than exhausted plants from the spring planting, provided they aren't having to deal with very severe drought conditions/moisture stress.

Once I've met all my canning goals, I start yanking out plants as their vigor fades and productivity falls. I plant a lot, though, so tired plants are expendable. I never yank out all of them---and I use logic---the plants that still have loads of fruit on them are left in place until those fruit mature, and then I harvest the last of the fruit and yank out the plants. I leave enough tomato plants to keep us supplied with fresh tomatoes until the first freeze, but I don't keep enough plants that I have huge surpluses to can.

If the fruit are so small they aren't worth dealing with, then I vote for going ahead and removing them and sowing the cover crop. We love tomatoes, but I get tired of them late in the summer. You know how it is when you first start getting ripe ones----you eat each one as soon as it is ready and you enjoy every bite. Well, by the end of the summer, we are totally the opposite--staring at those tomatoes sitting there on the counter and telling ourselves that we really "ought to" eat those. When I start leaving tomatoes on the counter and no one even eats them, I really start yanking out the plants and replacing them with something else for fall. I used to think there was no such thing as too many tomatoes, but since then I have learned that we do get burned out on eating them constantly.

I'll tell you what, though. Despite all the above, when we are eating the very last fresh tomato of the season, it is a bittersweet experience because we know it will be months before we have more fresh, home-grown tomatoes.