Hot, humid weather this July Day. Stay cool. My tomato plant is having yellow leaves. What is it? How can I fix it?

image from ​A tomato in trouble: Yellowing, wilting leaves are classic signs of Fusarium wilt. Credit: Plant Pathology

GOOD morning this Monday.  It is warming up and humidity is coming back.  We had wind last night, strong wind but looks like just some leaves and small branches are down.  The fruit trees all fell, but I got them picked up.  We got .6 of rain, so I don’t have to water wagons, trees and shrubs today. 
Yesterday the Herb festival went very well.  There were 4 of us sharing the parking lot for the public boat ramp that was closed because of the high water.  I must tell you it was an awesome spot.  We had shade trees, it was on a flat surface, and it was easy access to all the vendors in the basketball court.  We all hope they can get that space next year.  We had many in wheelchairs, and walkers that found it very nice to be able to shop.  Thank you, Greene Garden Club, for an good experience even with the hot, humid day we had.  I brought back less plants so that was my goal.  As I told a few, Larry will be happy to not load up so many plants for back to the greenhouse.
After this hot, humid weather, I will be back out working with the plants.  I need to decide if I will keep the flats, plant the flats for my garden or compost.  I am here to help you during the week.  I have had some questions about hanging baskets , yes I have some nice ones yet that we planted later so if you need some for a spot in your garden you can stop in.  I have many annuals left, perennials are here, lilies are ready to bloom.  The shrubs look awesome with the rain, and still a nice selection of trees.    I might be working outside, or I might be in the house/office working on bookwork.  We have a camera so when I see you drive up, I will be out.  There is still time to plant and enjoy your gardens.  That is what I am doing planting and enjoying. 
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Our weather, as all of you know is warm and heat advisory again from 12noon to 8PM.  Potential for overnight severe storms again tonight.  High today of 87F(31C).  Stay cool, stay safe

Australia weather for family and friends for Tuesday July 29. You might be wondering what time it is for them when I post this.  It is 10:50 AM on Monday morning here in Dougherty, and for them it is 1:50 AM Tuesday morning.  Their low will be 42F(5c)  and a high of 57F(14C).  For them they wear winter clothing. They are having wind so it will feel colder for them. Stay warm, stay safe.

Keeping Your Tomatoes Healthy
Tomato leaf problems can be frustrating, but they’re not the end of your harvest. With a little observation, a few preventive steps, and the right variety, most issues can be managed before they take hold.
As always, healthy soil and attentive gardening are your best defense. Keep a journal, note what worked (and what didn’t), and don’t be afraid to try new varieties next season. After all, every great tomato gardener learns a little more each year. 
I am going to share with you several things that can happen to your tomatoes. I will be posting each one separately so you can study each one.  Hopefully you are not having any trouble but if you are hopeful this helps. 

1st problem
Yellowing Tomato Leaves  Fusarium wilt disease on tomato
Tomato leaves turning yellow are a general indicator that something is wrong, similar to when humans have a fever. While poor nutrition can be a cause, when discussing tomato diseases, there are typically additional signs, such as wilting or spots on the stems and leaves.
However, if entire leaves are turning yellow, a likely culprit is Fusarium wilt, caused by the fungal organism Fusarium oxysporum. Warmer summer soil temperatures bring on this problem, allowing the fungus to gain a foothold in the plant through injuries to the roots caused by cultivation, nematodes, moles, or even vigorous weeding. Once in the plant, the fungus clogs the water-conducting tissue (xylem) and inhibits water transport, causing the plant to wilt.
Yellowing leaves, especially without other symptoms, are a good indicator. Remove infected plants, choose resistant varieties, and sanitize your garden tools. If you have continual problems, try soil solarization.
Resistant varieties: ‘Celebrity Plus’, ‘Supersweet 100’, ‘Early Girl’, ‘Jolene’, ‘Plum Regal’
Prevention and Monitoring
Of course, we would rather not have any Fusarium spores or hyphae at all. Monitoring will alert you to a developing problem. Prevention ideas include:
Purchase transplants and seeds from a reliable supplier. Seeds can be heat-treated or fumigated by the vendor to ensure no spores are hiding in your seed packets. A professional nursery or grower will monitor and take steps to keep their stock Fusarium wilt-free.
Clean your tools. Do this for tools used in potentially contaminated areas before moving to a new spot and before storing them for the winter. After scrubbing them, dip your tools in a mild bleach solution.
Fusarium fungi prefer acidic soils, so liming to raise your pH to be neutral or slightly alkaline  (soil pH of 7 or a touch higher) can limit their activity. Don’t overdo it. Highly alkaline pH can limit plant nutrient availability.
Choose Resistant Plants
Gardeners have many options when choosing which varieties to plant; some have been bred to resist Fusarium. The seed catalog or website listing will often state a particular cultivar’s resistance to Fusarium, Verticillium, harmful nematodes, and many other pests and diseases.
If you have previously experienced a problem with a particular pest, choosing a resistant variety is perhaps one of the most important and easiest ways to minimize the impact.
You may see the resistance abbreviated as ‘F’ or ‘FNV.’ The latter would indicate resistance to Fusarium, nematodes (the bad ones), and Verticillium. Seeds labeled ‘TMV’ would show resistance to the tomato mosaic virus.
Tomato seed may be labeled ‘F’, ‘FF’ or ‘FFF’ to indicate resistance to one or more races of F. oxysporum f.sp. Lycopersici. Check the key or legend of your seed catalog to confirm.
Treatments for Fusarium Wilt
There is no “cure” for Fusarium wilt. Fungicides are not effective. Your best bet is to limit the spread and food source, and choose resistant plants, as discussed above.
Get rid of infested plants
Remove infected plants. Don’t compost them. Bury them (somewhere else) or burn them. Getting rid of these infected plants can reduce the amount of spore present next year and slow the spread.
Move plants around
Rotate your plants. For example, if you experienced Fusarium wilt in your tomatoes, move next year’s tomato planting to a new area and grow a non-susceptible plant in the old spot. (This is known as “crop rotation.”)
Fusarium is host-specific, so the fungus that attacked your tomatoes likely won’t bother your melons, beans, etc. Don’t replant a susceptible species for several years. Avoid planting a related species in that location, like following tomatoes with peppers (they are both members of the Nightshade family, Solanaceae).
Use soil solarization
Fusarium spores in the soil may be killed by a technique called soil solarization. Basically, bare ground is covered in clear plastic to harness the sun’s rays and heat the earth, killing the pathogen.
The process can take several weeks during the summer, so you may have to forfeit the peak of the growing season. However, you can still plant a late crop of delicious lettuces, kale, and peas, right?
Fusarium wilt can be challenging if allowed to spread in your garden. Take the actions given above early. Choosing resistant varieties, rotating crops, and cleaning your tools will go a long way toward keep Fusarium risk low.
Taken from https://www.almanac.com/whats-wrong-my-tomato-plant-visual-guide-leaf-problems
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