If you can keep them healthy and growing that long then you very likely will get some production from them. Many of us have to baby our plants thru these summer doldrums.

However, IMO the production you will get won't match the production you could get from fresh plants put out at the right time for your Fall tomato season. I baby my best plants through but I also plant new ones for Fall and my Fall season is much shorter than yours.

So if you have the space I'd suggest getting some new ones started now to either replace any of the current ones who aren't fully healthy and also to have to plant for your Fall season. That would give you the best of both situations.

Dave

they are currently doing well, i guess my question is: does a healthy older plant produce more than a growing young one?

As I said above, no. When the growing season is long enough for the young plant to reach maturity, it will out-produce the old one. Is a 60 year old normally as physically productive as a 25 year old?

The circulation system in the older plant has had to cope with a long period of stress and has much more growth to support and has to work harder. It shifts its focus to the secondary and other distal branches, not the core of the plant. That usually means less blooms and smaller fruit - weaker muscle tissue and more varicose veins. ;-)

Dave

Cut the growing tips. I don't exactly know if this will work in your climate but it always works in my humid (but not hot) climate.

Also cut any of the smaller suckers completely.

I'd be tempted to keep them, NOT cut the growing tips, and in fact remove the oldest leaves at the bottom of the plant as they start to go off. Maybe start some new ones too, from seed.