If it's a phosphorous deficiency caused by the cold, they should bounce back when the weather warms, and there's no need to give up on them. I grow my seedlings in a chilly basement and they look purple as a result, but it doesn't take long for them to turn green :).

Thank you - how quickly? A few days?

I should think so.

A phosphorus deficiency is not caused by cold. The two phenomenas are quite independent of each other. Lack of phosphorus is a soil issue - purpling due to cold temperatures has nothing to do with the plant's ability to uptake P but has everything to so with nighttime temps that dip below 50F. And is not restricted to tomatoes but also other plants that are sensitive to cold temperatures, especially over night.

Cold temperatures inhibit a plants ability to absorb phosphorous. The temp in my area has been above 60 since May until last week where we had an atypical cold spell which is when this started. And the problem is with my tomatoes only.

when were they transplanted? ... add that stress to cold stress.. and come to the conclusion your plants are stressed ..

and then just be patient ...

anything grown in a media.. for spring planted.. is not going to show nutrient deficiencies inside a few days or even weeks ... if by august.. your plants are still showing some problem .. then maybe you have a soil issue ...

but with Ts .... they ost important thing to remember.. is they are hothouse girlfriends ... you will see them in their prime when outside is the equivalent of a hothouse ... which is july and august ... for most of us.. late may .. when this started.. is not hothouse weather ...

be patient.. lets make sure not to fix.. what probably isnt broken ... or its too soon to tell if its broken ...

and next year.. maybe plant them a week later.. and avoid cold issues ... but then.. ma nature will screw with that idea.. lol ... like she did this year .. what is her deal ...

ken