I have some tomatoes that I've grown from seed that are now green however I don't the best time to pick them. Should I leave them on the vine to ripen or best pick now and hope they turn red in the fridge? Any advise would be useful.
I'd leave on the plant,take off all the leaves that are covering the trusses,take the top out to leave about 4or5 trusses.That will help, If there is a frost I'd pick them.When there is a frost cut the whole truss off and put it in a drawer with a banana,that will help it to ripen,don't put them in the fridge they won't ripen.
would this also work with chilly plant that aren't fully ready yet?
No it doesn't work with chillies,you'll have to be patient they will ripen but slowly, now that autumn is here.
And can't you just use the green chillies as normal? Do they have to be red?
Hogweed yes you can use them when green,they won't be so hot.