Hardiness Zone: 10a
mitch914 from South Texas
Many insect and disease problems cause yellow leaves on a tomato plant. The problem could be cultural: too much water, not enough water, poor drainage, not enough sun, wrong ambient temperature, leaf scorch caused by dry, hot conditions following cloudy moist conditions (this can cause a sudden water loss in the outer portion of the leaves) or a build-up of salts from fertilizer.
It is hard for me to tell from your picture, but are any of the lower leaves turning yellow, or is it just the newer leaves? Do the leaves contain spots or rings? Do any of the following "yellow leaf" symptoms sound familiar?
Yellow or pale colored leaves: This could be caused by a nutrient deficiency. Here are some common symptoms:
Yellow patches on leaves that contain brown concentrically ringed spots: This could be a sign of early blight. Spray copper or bordeaux mixture and repeat every 7-10 days.
Older leaves yellow; shoots (or whole plant) wilts: This could be Fusarium or Verticillium wilt. These two fungal diseases both begin with the wilting of lower leaves. The plants are stunted and do not recover when watered. When cut open, stems and shoots will show some internal discoloration. Toss affected plant and replace them with disease resistant varieties and new soil.
Leaves are yellow (may contain brown spots); leaves are also distorted and sticky: This could be a possible aphid or white fly infestation. Look for small sap-sucking insects (green, black, white, or pink in color) on the undersides of leaves and traces of honeydew on the leaves (sticky substance). Insects may also fly away when disturbed. Spray plants with a strong jet of water or insecticidal soap to remove.
Leaves are yellow; the plant is stunted and eventually wilts in hot weather: This could be a sign of Root Knot Nematode damage. Plants will have swollen galls on roots and eventually die. This is not as common in plants grown in new commercial potting soil.
Leaves mottled yellow; young growth appears narrow and twisted: This is most likely tobacco virus. Plants should be destroyed and replaced with a disease resistant variety planted in new soil.
Leaves speckled with yellow dots; fine webbing on leaves: Most likely spider mites. Spray them off with a strong stream of water from the garden hose, or use insecticidal soap.
I hope these ideas help!
Might be lack of magnesium or iron.
About cigarette butts, NO!
It's true that nicotine can be used to fight certain problems in the garden in liquid form, but it is poisonous, and can be absorbed through the skin.
Cigarettes contain nicotine which is probably why it was helpful. However, tobacco can carry a virus (not saying that it will, but it can), that will wipe out your tomatoes. So you are taking a risk getting the nicotine in that form. If you use the liquid form, don't let children/pets near plants and keep it safely put up.
Yes! Cigarettes work! I know it sounds awful, but it is true. I also heard this on a gardening radio show. I tried this, I purchased a pack of cigarettes and broke them up and put into the dirt around 2 of my 8 plants. Yes, they grew like crazy. Try it. I'm not sure if it will correct the yellowing (which I've always had happen when I don't water on a strict schedule, avoiding over watering and under watering), but you can have a little fun watching the difference in your plants! Good luck to you! (03/03/2008)
This actually looks like nematode damage. They are microscopic "worms" that feed on the roots. That may be why some people are saying to put cigarettes in the soil because that might just work, but tobacco can carry mosaic virus and is sprayed with many, various pesticides - not something you want on your tomato plants. Try growing them in a container with potting soil and see if the same thing happens. (03/04/2008)
I am an agriculture student and we are doing a study right now with nemetodes and the new growth turning yellow looks just like nemtode damage. When older growth turning yellow is another problem, could be nutrient or the early stages of fusarium or verticillium wilt. Both are soil born problems that really can't be fixed except to grow your tomatoes in containers with sterile potting soil. (03/06/2008)
I started my tomato plants from seed and they all have germinated within 10 days like they have for the last couple of years, but the leaves have turned yellow and i don't know why. I don't smoke, water them regularly keep them in a warm, dry place and they have at least 7 hours of artificial light every day. Anyone have any suggestions?
Editor's Note Yellow leaves is often caused by too much watering. (03/29/2008)
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