Some of my tomato plants have yellow leaves. These yellow leaves are the first leaf and second leaf of the tomato plants.
There are several reasons for the tomato plants leaves to turn yellow. I am trying to find out which one is the reason for the tomato plants leaves to turn yellow.
The first reason could be the tomato plants have not getting enough water.
The second reason could be the tomato plants have too much of water.
The third reason could be the tomato plants do not have enough nitrogen from soil.
These are the three reasons I am thinking of and trying to find out one which makes the tomato plants leaves turn yellow.
They have more than two leaves. The bottom leaves on these plants turned yellow.
Some plants have one leaf at the bottom of the plant turned yellow. The others have two leaves at the bottom of the plant turned yellow.
Well, I'm no expert on tomato plants in particular, but in some plants, each leaf has a limited expected life span, and when that's up, the old leaves die off to make room for new ones.
It could be the case that this is what's happening here.
At any rate, if they all have a bunch of healthy leaves, I wouldn't worry about losing just one or two per plant, as long as the dying leaves don't show evidence of fungus or bugs or anything.
I think most likely the plants were getting too much water.
So their lower leaves turned yellow.
It was raining for several days.
They looked a bit wilted.
Sorry about your tomatoes! Yellowing leaves and dying stems are symptoms of several problems. But keep in mind that they rarely appear alone. Usually, your tomatoes give you another clue to diagnose the problem. Study your plants carefully. Use this checklist to help figure out which situation fits you.
Over-watering or under-watering. If your season has been especially wet and cool, your tomatoes may be "drowning." Water can clog air pockets in the soil and prevent plants from getting needed air. On the other hand, if you're in a heat wave with excessive temperatures, your plants could be over-stressed and under-watered, which could cause them to drop leaves. Make sure plants are getting 1-3 inches of water a week - on the high end of that if it's hot and on the low end if it's cool.
Early blight or Septoria leaf spot. Yellowing leaves are a symptom for both diseases. To tell the difference, check to see if there are spots on the leaves. Early blight exhibits dark concentric circles on leaves and stems. Septoria leaf spot presents small dark spots on the lower leaves. Read more about different kinds of tomato blight and how to tell them apart.
Tomato wilts. Fusarium wilt and verticillium wilt also exhibit yellowed leaves. Fusarium often just affects one side of the plant. Verticillium encircles the plant, but the yellowed pattern on leaves is V-shaped.
Curly top virus. Infected plants turn yellow and stop growing.
Pests. Aphids, whiteflies, flea beetles, tomato hornworm and tobacco hornworm, and psyllids attack tomato plants and leave holes, dew, or chewing injuries to plants -- in addition to yellowed leaves. Check undersides of leaves and along stems for pests!
Most tomato problems are treatable once you identify the source. Track rain and watering patterns (to see if it's a watering issue). Study the yellowing pattern in the leaves (to see if it's caused by a disease). Look for other additional damage (to see if it's caused by a pest).