I had literally hundreds upon hundreds of volunteer tomatoes of all types in the garden this year...having done the stupid trick of emptying all my tomato canning scraps into the deep litter of the coop for the chickens to enjoy. Then, using that composted litter on the garden, never thinking for a moment about all those tiny tomato seeds that had spent the winter fermenting in compost, just waiting to spring into action.
The healthiest, biggest tomato plants I had this year were the volunteers that I allowed to exist...none of which contracted the fungal blight like the tomatoes I planted intentionally. Two of these volunteers were beefsteak variety and were bearing just fine, even though I didn't sucker them or stake them....but they were located just outside of the garden and the deer ate the plant and the tomatoes, while the chickens ate the rest of the tomatoes.
Most of the volunteers inside the garden were Roma or grape/cherry tomatoes...the ones I didn't pull up while still little all bore fruit and plenty of it..and are still out there putting out tomatoes like crazy.
I'm thinking of doing intentional "volunteer" sowing late in the fall of the seeds I want to see growing in the spring. I'll do it in a cold frame to see if I can give them a little extra warmth and nutrition while they get started in the spring. Don't know if that will work but I'm game to try it.
I'll let y'all know how it goes.