My tomato leaves turned purple?

They were given magnesium, potassium, phosphorus and every kind of tonic I could find - in succession. not all at once......

The leaves at the top of each plant turned purple and practically stopped growing. The tomatoes lower down ripened normally. Very odd.

I can only think of lack of magnesium.

Not mildew, no.
My brown tomatoes came from China!
My best ones, though, came from a cross the year before, Sweet Million (tiny salad toms) X big beef toms (forgotten what kind).....large and sweet as well. I kept seed to see what happened.

Alie my 'Black Russian' tomatoes were a weird shade of brown but delicious to eat.

Cold can do it. It's not a mildew is it? my garden has had a lot of that This year. The clematis were wilting right left and centre. Me included

Mine didn't recover with phosphorus......

I had supposed-to-be purple ones too but they were brown, and I don't know if they were right or not!

I had purple tomatoes, but they were suppose to be that colour!

I think it is cold and/or a shortage of potash, either because the compost is deficient in it or because they can't take it up so well when they are cold - but it might have been phosphorus.

I was always lead to believe it was the cold that turned them purple but hardly applies to during the summer

Dunno what you could do about it, though!

Well, how strange. Ours have been fine, but it's something to look out for. I must tell my DH about it when he comes back from Scotland.