HelpfulGardener.com

I have sungold and black cherry tomatoes growing in 5 gallon buckets. The leaves are starting to turn a dark purplish hue. I water them every day (they dry out quickly) and fertilized them a couple of times.

Is this a disease or possibly a nutrient deficiency?

Tends to happen when temperatures are cool and or the soil is staying wet. I think it is a nutrient deficiency (phosphorus?) that is caused by the conditions making it difficult for the plant to uptake the nutrient.

Usually goes away on its own after things warm up and dry out.

Thanks. It's been warmer here than normal for our "winter" - 80s during the day, 60s at night. I was watering them every day since the top of the soil seemed dry each morning. So do you think I should fertilize them more or just wait a longer time between watering?

Hi
Could it be this? ?

https://edis.ifas.ufl.edu/document_pp259

Really interesting... that seems to completely describe it. It hasn't affected the veins and is appearing on the leaves more exposed to sunlight. Thanks for the article link.

Glad to help. What are you going to do? Nobody seems to know what it is. Too bad since sungold is one of the sweetest tomatoes but it has very poor disease resistance.

Thanks, imafan, interesting. I did actually think that the purpling I was talking about tends to occur more on the under side of the leaves, but probably didn't pay enough attention to that. I never heard of the tomato purple leaf disease before. Just what we need, new diseases!

Sounds nasty! Fungal diseases in tomatoes (of which there are many), tend to be treatable, with varying degrees of success. Viral diseases generally nothing to do.

I have been growing tomatoes for over 30 years and for the past 6 years growing them in self watering containers. This year, the leaves on all of my tomato plants started to turn purple. Since I do live in a farming area, I checked with tomato farmers and this problem has not been seen by them. Several of the farmers believe that the fertilizer used could be the problem. I have been purchasing fertilizer from the same company for the past six years and this year, the packaging of the fertilizer changed. This problem could have been caused by the fertilizer that I used this year.

I hope that is the problem. At least it would be fixable.