A few weeks after transplanting outside, one of my tomato plants started developing yellow leaves. I thought maybe I hadn’t watered it enough. Another week passed with more water and more yellow leaves. Something is wrong here. I checked the leaves for aphids and didn’t see any. Not all the leaves are turning yellow and they didn’t start from the bottom. The yellowing seems to spread around the plant. According to some of the plant health sites I visited this could be a fungus or some other pest, but I’m really not sure. I usually have good luck with tomatoes.
I’m not fond of using pesticides, fungicides or other chemicals on my plants, so I decided on another approach. I cut off all the yellow leaves and threw them away. The plant looks better, but I can tell it’s not thriving. I’ll let it continue to grow as long as it will, but once fall comes, I’m going to cover the soil in that garden with plastic to sterilize what ever is in there that is not friendly. I’m also planning a new garden with a little more direct sun. I’ve grown tomatoes in the same spot for 3 years now. It’s probably a good time to rotate and grow them elsewhere. We’ll see what happens.