Q.Tomato Plants leaves turn yellow bottom up
My tomato plants grew just fine and fast with healthy green leaves. After maturity and fruits after 3 months, all leaves turn yellow and then dry brown from bottom up. Is it a nutrient deficiency or a pest problem?
Tomatoes can be effected by the environment, insects and many bacterial or fungal diseases.
Do a closer examination of the leaves to help correctly diagnose.
Check watering, too much or too little can cause the yellowing leaves.
Proper draining soil to avoid any root rot is important.
A soil test can be done to help determine if the issue is nutrition based.
Use caution in fertilizing and do not use to much nitrogen.
Has this been a recurring issue? Crop rotation is very important to avoid soil born diseases.
The links below will help you match the symptoms.
https://www.gardeningknowhow.com/edible/vegetables/tomato/blight-infected-tomatoes.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-plant-problems.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/yellow-tomato-leaves.htm
https://www.gardeningknowhow.com/plant-problems/environmental/leaf-chlorosis-and-iron.htm
https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-fertilizer.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/calcium-fertilizer.htm