I keep having problems with my tomato plants starting to turn yellow and die from the bottom leaves up, usually when they've gotten a foot or so tall, and usually anywhere from well before to right in the middle of producing several tomatoes at the top that continue to grow until the yellowing reaches them. The plants continue to grow and produce, but the yellowing also continues to crawl up them. I do feed them and keep them well watered, so I'm not sure what else the problem may be.
All I do know is that I never remember having this problem 20 years ago, whether they were fed or not - and it's more likely that they were not at that time.
Any help is more than appreciated. Thanks!