Hi Sparky, you can pick them as they mature or use some as immature ones. The simple rule is , if they are cured and OK to store your fingernail won't penetrate easily.
Re feeding them, I doubt there is much to be gained by feeding now, it has been a bad year. Even on a withered yellow vine the plants are getting nourishment.
I just picked tomatoes off Tumbler plants, I only grow a couple as they are not my favourite flavour but they are the earliest to fruit and when the others come along I leave them to die off.
They haven't been watered for about a month now and the foliage is brittle and dried brown, but the tomatoes have still been ripening on an apparently dead plant. I have just got about 5 pounds from 2 plants.
As the winter draws in, I often leave toms on a vine rather than pull them green.
We just leave the plants in the garage or greenhouse in the pots and stop watering them, they ripen for weks like this.
Once they are severed from the plants they cannot get any nourishment, you would be surprised with your squash just how much more they can get from a withered Mum.
XX Jeannine
