Lower leaves yellowing, black spots, dark veins, getting worse

[wodawiatr]

Hi! Great forum. I have been searching high and low for a diagnosis for my tomato plants and I can't find anything conclusive.
I am growing cherry tomatoes in a pot on my balcony - they were started from seed and grew wonderfully fast. Over the past two to three weeks, the biggest leaves in full sun near the bottom have started yellowing. The problem is working its way up the plant and they are getting black spots, curling up, and have dark veins. Initially I wasn't worried because it was confined to the lower leaves only but now it is steadily working its way into the newer growth. I fertilise them with an organic fertiliser once a week or so and I am trying to be careful to not overwater them.
I have put some pictures of them here:



http://www.dropbox.com/gallery/63085...b/pom?h=beedce


Is there anything I can do? The tomatoes are growing but I'm concerned that the problem will worsen.


Thanks a lot!


Kolin

[RayR]

They are most likely getting root bound in that small planter. The purple veins and the yellowing is usually a sign that the plants are having a hard time taking up nutrients, which happens when there is more roots than soil area down there.

[wodawiatr]

Hi Ray, thanks for the feedback. I had wondered if they were just getting root bound but the strange thing to me was how it is the leaves in the brightest sun that are yellowing. Next year it will be a smaller planter . . . you can see from the size of my 'balcony' that I am somewhat restricted!

All the best,

K