[Scribbler]

Huge crop of green tomatoes - they weren't getting enough light in the greenhouse. So harvested them all and brought them, indoors to make green tomato chutney.

Lo and behold, either in the sun or in deep bowl shared with bananas, they are all ripening. As a result, I've got more tomatoes this year than ever before.

While I'm on, for all the challenges faced this year, I had broad beans without blackfly for the first time ever. Don't know why. Wasps eat aphids, but practically no wasps this year. Local council has had three calls about wasp nests this year compared with over a hundred last year.   

[GrannieAnnie]

They do say to put a banana in with you green tomatoes to help ripen

[stompy]

Bananas release a gas called Ethelyne that ripens all other fruits, apples do too but not as much as bananas.
Put a couple of bananas in a confined place, fruit bowl drawer or paper bag with some of your green toms and they will ripen them.
I used to put banana skins in my greenhouse to aid ripening.

Andy

[A Reyt Tayty]

I hang them over the plants themselves. Seems to work fine.

[JayG]

Ripening tomatoes produce their own ethylene (although not as much as bananas.)

I find that a mixture of partly-ripe and unripe tomatoes in layers no more than 2-3 deep (to help contain the ethylene but avoid bruising them) all ripen very well on a warm sunny windowsill, although very green and undersized toms usually just stay green and eventually shrink (best if they have at least a hint of yellow on them.)

Take out the ripe ones when ready and add more unripe ones (if available!)