Why are my tomato plants turning yellow on the bottom and going up the middle?
The Gardener’s Answer
Hi, Caroline: Tomatoes are susceptible to many different diseases. Choosing disease resistant-cultivars and providing optimal growing conditions can make all the difference in terms of growing healthy, productive plants. Do you know which tomato you are growing and is it producing healthy fruit? From what you have described, and the look of the lower plant, Magnesium deficiency is a possibility. If you have not had your soil tested, you can contact your County Cooperative Extension office to have this done. You can also take a sample of your plant to the agriculture/horticulture agent(s) to get a positive diagnosis. When plants are not given optimal growing conditions they are more prone to other problems. I also looks like could also be dealing with a fungus known as Septoria leaf spot. It is important to remove and dispose of all infected foliage and weed around the base of the plant. If plant material is left behind it can overwinter in the soil and the same problem will occur next year. Always avoid overhead watering and crowding your plants. Good air circulation is helpful in preventing diseases. If you have been growing tomatoes in the same space for several years, it may be time to rotate your crops. maintaining even soil moisture is always a good idea. Thanks for sending the picture- it is always helpful to have a visual when answering questions.