It might be red spider mite. Every year when I grew them they succumbed to the dreaded mite. All I can suggest is that you keep them misted with a fine spray of water and damp the floor of the greenhouse if you can.

Thanks Cammomile , that's exactly what I've done ... Every day they have been misted and every day I have dampened the floor to keep the greenhouse humid. I have been very careful not to do the floor later on in the day in case it just feels cold and damp . Honestly , I have treated them like babies and done everything imaginable ! I wonder if I've cosseted them too much ?

No you haven't. I did try some 'bugs' that you get from a company called Ladybird which you release onto the leaves, but by the time I got them I had lost the plants. They seem to go downhill very quickly don't they.

Cammomile , I know it defeats the purpose of the whole organic thing but do you think I could spray them with Provado or something similar ?

They are indoor Bilbo ... They even have a separate wee section of the greenhouse that I can keep nice and humid. I do give them quite a lot of water but never enough that there is water sitting in the saucers - maybe I still give them too much. Does it sound to you like they are past the point of no return ? Just like Cammomile said - I am gobsmacked at how quickly they turned !

Hi Bilbo , Thankyou so very much for such a comprehensive explanation. The leaves are very yellowy and mosaic like but I have thoroughly inspected them and not one sign of spiders or aphids etc so I guess it is all down to me with careless watering ! I thought they quite like to be misted with a fine water spray so I've been doing that too ! Honestly though I think I have to hold my hands up and admit to not only watering them far too much but also being very clumsy about it ! I won't give up and I'll try again next year only this time I am loaded with much more information thanks to you and all the GOYers. Can't help feeling rather silly though !!!

Mosaic on the leaves sounds like red spider mite to me. You could look for webbing around the leaves. I have been known to pull the wretched plants out and start again when this happens. I haven't grown them this year as I lost the use of the greenhouse.