My tomatoes leaves are curling and the plant is drying up. What could cause it? I know it was not drift from chemicals, I have had the soil tested, I have been watering. You will be surprised at the answer.

image from gardenvive.com

My tomatoes are drying up and dying.  I know it was not drift from chemicals.  I have had the soil tested, I have been watering.  You will be surprised at the answer.

​Good morning, as I can see this is going to be a perfect day.  Mild temperatures, wind out of the NW and clear, blue sky, low humidity.  Enjoy today as it is going to change. High today of 77F(25C) 13ENJOY, stay cool, stay safe.
 
Australia family and friends for June 26th Friday will have a high of 58F(13C) I heard from one of the friends and she said it is a mild winter for them.  Enjoy, stay warm, stay safe. 
 
Many gardeners have been coming and picking up tomatoes as they have had theirs die.  I just learned this, during this season.  Cold night temperatures caused this problem this year.  I know you can’t believe it but here is an article that talks about it, and it makes sense.  This spring even in May we had cold nights and the soil was cold.  More so than other years, that is why we are having this problem now.   Also extreme heat can do this too, but we haven’t had that much extreme heat till next week I am afraid. 
 
Tomato Leaves Drying Up
Are your tomato leaves drying up this year? Then you are not alone, a lot of other gardeners are facing the same issue with their tomato plants
NOTE: Tomato leaves do not dry up just because of a single specific reason; there can be multiple causes.
Tomato Leaves Drying Due to Extreme Cold
Tomatoes can be grown nicely when the temperature is between 70°F – 85°F during the day and 59°F – 70°F at night.
But most of us forget the soil temperature. It should be 65°F – 70°F.
 
This temperature range is ideal for growing your tomato plant. But it does not mean that it can not handle colder nights or warmer days.
If temperatures drop below 50°F consistently, your tomato plant will go into stress. This stress can cause the green leaves to dry.
So, keep your weather alert application ready or check the weather forecast regularly if you are from a colder region.
Using a frost cloth is a must if it's below 41°F (5°C). Reference: When to cover plants in winter.
If your tomato plant is potted, bring it inside.
If your tomato plants are drying up due to the cold, it will not start with browning first. The green leaves will become crunchier and crunchier until the leaves dry up completely.
Till now, I have talked about the most possible reasons for dry leaves on a tomato plant.
Now, I’ll discuss a few more points that will clear up many of your doubts and confusion.
If you notice that only the lower leaves are getting dry, this is normal, and there is no need to worry about this.
If you see, only the edges of the leaves are drying up, it's surely underwatering. Water deeply in the morning (As early as possible).
 
 
This happens when the heat increases suddenly. (To be more specific, when it's above 90F)
So, how can you tell whether it’s caused by heat or something else?
Leaves usually curl upward and feel leathery instead of crunchy.
What to do in this situation?
Mist water in the evening and morning on the plant, especially if flowers are falling off.
Use 30% to 40% shade cloth. Use frames so that the cloth does not touch the plant leaves or branches.
If the cloth touches the plant, it will burn more.
Do not prune at this stage. The dry leaves actually can provide some sort of shade to the plant and check for white spots, powdery mildew, or mold.
If the leaves are infected, prune without hesitation.
Taken from https://gardenvive.com/tomato-leaves-drying-up/
 Till next time this is Becky Litterer , Becky’s Greenhouse, Dougherty Iowa [email protected]  641-794-3337  cell 641-903-9365  Beckysgreenhouse.com  Facebook Becky Kerndt Litterer or Becky’s Greenhouse