Common Tomato Problems

This important information is shared with us by Robert R Westerfield, College of Agricultural and Environmental Sciences, Extension Horticulturist. He is our vegetable guru.


The tomato is the most commonly-grown vegetable in America. Unfortunately, producing big, red, juicy tomatoes requires considerable effort in preventing and controlling diseases.

tomatoslices

Select tomato varieties that are disease resistant. This is very important! This may be your only chance to control certain diseases. The letters behind a variety’s name tell what diseases it is resistant to: T-Tobacco Mosaic Virus, V-Verticillium Wilt, F-Fusarium wilt and N-Nematodes, some good possibilities are Celebrity and Better bush but there are many others. Resistance does not mean the plants are immune to these diseases.

Move tomatoes away from where they or potatoes, eggplant or peppers were planted last year. Soils in these areas may harbor leftover diseases. Bury all plant debris when tilling and keep mulches pulled back an inch or two from the stem.

You can plant tomatoes in a traditional vegetable garden, a raised bed or put a few plants in a flower garden. I would avoid potted tomatoes because they require extra care in watering. If you grow potted tomatoes-use 5 gallon or larger pots. Water until water runs out the drain holes and then let the soil dry slightly before watering again.

The number one tomato disease now is Tomato Spotted Wilt Virus (TSWV). It is spread by thrips. Usually the top of the plant looks stunted or wilted. The young leaves may turn yellow and often have brown or black discoloration in them. The veins on the underside of leaves may thicken and turn purple. Fruit can have raised or flat rings or circles on them. Ripe fruit will have yellow circles or semicircles. The stem can have long brown lesions.

Once tomatoes get the disease, there is no control. There are two varieties of tomato that are resistant to TSWV. I have not yet seen them yet in stores. Spraying for thrips is also not effective.

Destroy infected plants as quickly as possible early in the season to prevent spread. Seal them up in a plastic bag. Even after the plant is pulled up thrips can leave it to spread the virus. Late in the season you may just want to let the infected plants finish ripening the fruit they have. Late season infection is less of a concern.

A fungus causes Fusarium wilt. It blocks the water conducting tissues in the plant. The leaves yellow and wilt, often starting at the bottom of the plant. This disease can affect just one side or one to several branches of the plant. The plant can die early producing no fruit. If you cut into the plant, the vascular system (just under the bark) will be brown. Control Fusarium wilt by planting resistant varieties. The ‘F’ after the name, like Celebrity VFN identifies these. Fusarium wilt can survive in the soil. Do not plant tomatoes in infected areas more than once every four years.

Bacterial wilt causes a rapid wilting and death of the plant. The plant dies so quickly it does not have time to yellow. To identify Bacterial wilt, cut through the stem. Bacterial wilt browns the pith or middle of the stem. On bad infections, the pith may be hollow. Cut a short section of the stem and suspend it in a clear glass of water. You can often see a milky ooze streaming out of the bottom of the cut stem. There are no controls or resistant varieties for bacterial wilt. It also attacks peppers, potatoes and eggplant. Carefully dig out infected plants and soil and discard. Do not plant any of these vegetables in this area for at least four years.
Southern blight is a white mold that rots the stem at or near the soil line. The plant then wilts or dies. Look for the cottony fungus growth and the light brown BB-sized fruiting structures of the fungus. The fungus may be slightly above or below the soil line. You may not see the fungus growing on infected plants when the weather is dry.

Bury all plant residues before planting, plant vegetables farther apart, and treat with Terraclor at planting if you have a problem with Southern blight. Some people wrap the stem near the soil line with foil to slow this disease and to control cutworms. The foil must extend two inches above and below the soil line.

Blossom-end rot (BER) appears as a dry leathery spot on the blossom end of tomatoes. It can also affect peppers and watermelons. The spot is usually on the blossom end, is tough and leathery and slightly sunken. Other rots may infect this spot. These fruits may turn red first.

BER is caused by lack of calcium in the blossom end of the fruit. By the time the tomato reaches the size of a nickel it has most of the calcium that it will ever have. This is why we need to prevent blossom end rot early. Inadequate water supply, low pH or low soil calcium levels can cause this problem. Find and correct these problems.

Once a plant has BER, it is hard to control. Calcium is best taken up by the roots so sprays are not very effective. Control and prevent BER by:

  • Water the plants well and let the soil dry between waterings. A sample watering schedule is three-quarter inch twice a week if there is no rain.
  • Apply a two to three inch mulch around the plant. Do not heavily prune the plant.
  • Soil sample and lime and fertilize as needed. Avoid large applications of high nitrogen fertilizers when fruit are small.
  • Add gypsum (calcium sulfate) or lime to the soil at planting. Mix a cup in each planting hole or use one pound per 100 square feet. You can apply this once you see the problem but these treatments work slowly. Plants often appear to grow out of the problem as conditions improve.

For further information. Tomatoes flowers will not set fruit if temperatures are not right, if the plant is water stressed or if it already has enough fruit. Night temperatures should be 55o to 75o F. for best fruiting. Night temperatures above 90o will especially cause problems. Water twice a week (3/4 inch each time) and mulch plants. There is a blossom set chemical you can spray if you can locate it in the garden centers.

Leaf Rolling occurs when the plant has set a heavy load of fruit and the light intensity is high. It can be caused by wet soils. The condition is harmless and should not hurt final production. Prune less heavily and plant in a well-drained area.

Uneven ripening occurs as grey or white spots inside the fruit. Several factors can be involved including improper nutrition, high temperature and disease. The only thing we can correct is nutrition. Do not use too much nitrogen and/or too little potassium. Soil sample and fertilize accordingly. Use high potassium fertilizers, 5-10-15, 15-0-15 especially as fruits begin to get larger than a quarter.

Fruit cracking is due to rapid growth after periods of slow growth. Rain after drought and heavy fertilization can cause fruit cracking. Harvest fruits after they begin to turn red but before they crack. Follow the watering practices we have discussed and look for cracking resistant varieties.

Catfacing is caused by cool temperatures at time of pollination. The fruit is deformed with ‘zippers’ on the skin. The fruit can have lobes, tear drops or several blossom scars. Plant resistant varieties, plant later, or use row covers to increase the temperature on cool days and nights. The large beefsteak varieties appear to be more susceptible. The fruit is still edible.

Sun scald appears as a white blistered area on the top of the tomato. Do not prune heavily and maintain nutrition and pest control so as to provide a good leafy cover for the fruits. Be careful not to confuse this with Blossom End Rot.


Resource(s): Vegetable Gardening in Georgia

Center Publication Number: 100

Happy Gardening!

Tomato Planting 1,2,3

Now that you have chosen your tomato plants it is time to put them in the ground. There is a trick to planting tomatoes that helps them get through a long, dry, hot Georgia summer.

Snip off the lower leaves.
Snip off the lower leaves.

Step 1: Tomatoes need full sun, 8 hours, for setting fruit.  They also need well-drained, porous soil with a pH of about 6.2.  Plan on giving them at least 2 feet X 3 feet of growing space.  You will need to stake the plants or use wire cages to contain the plant growth.  Once you have your site ready, start with a healthy plant with a strong stem.  Notice the stem seems hairy.

Step 2:  Gently remove the lower leaves with snippers or by pinching them off with your fingers. Be careful not to make tears along the stem which would create wounds.  Leave the top two or three leaves.

20140412_112049
The hairs on the now buried stem will become roots creating a strong root system to better handle periods of drought.

Step 3:  Dig the hole deep enough so that you can bury the stem up to the remaining top leaves.  The part that is planted under the soil will develop roots creating a strong, deep root system that will help the plant better handle dry periods.

Press the soil around the plant so that a slight depression is formed for holding water.  These steps should get you one step closer to that BLT!

For more information about growing tomatoes see Robert Westerfield’s publication Georgia Home Grown Tomatoes.  For the best information for your area, contact your local UGA Extension Agent.

Happy Gardening!

 

 

 

Tomato Terminology for the Georgia Garden

Over the next weeks we will be exploring the world of tomatoes. They are the most popular plant in community gardens. But tomatoes can be problematic. Together we will share the good, the bad, and the delicious of tomato growing. Please share your experiences. To begin our tomato journey we are going to look at some tomato terminology.

Tomatoes in Hay BalesDeterminate vs. Indeterminate

When deciding on what type of tomato plants you want to grow, choose if you want determinate or indeterminate varieties.  Determinate plants bear all of their fruit at one time.  The plants tend to be more compact and easier to manage.  You will probably still need to support them with a tomato cage or staking.  Determinate varieties are popular with growers who want to preserve the fruit, make tomato sauces, or salsas as they get all the fruit at once.

Indeterminate varieties bear their fruit throughout the growing season.  The plants tend to sprawl and will definitely need support by staking or caging.  Growers who like to eat fresh tomatoes throughout the summer prefer indeterminate varieties.

Tomato Disease Resistance

Due to successful tomato breeding gardeners now can choose tomatoes that show resistance to the common diseases that plague all tomato growers.  A note of disclaimer here – remember that disease resistance does not mean disease proof.  You can easily determine the disease resistance of a particular variety by the initials after the name:

Big Boy VFN Tomatoes
Big Boy VFN Tomatoes

V – Resistance to the fungus that causes Verticillium wilt.

F, FF, or FFF – Resistance to the fungus that causes Fusarium wilt.  Sadly, some of the fungi developed immunities to the resistance qualities of the initial “F” tomatoes, so breeders developed cultivars that are resistant to the newer fungal races so now you may see “FF” and “FFF”.

N – Resistance to nematodes

T – Resistance to the Tobacco Mosaic Virus

TSWV– Resistance to the Tomato Spotted Wilted Virus

A – Resistance to the fungus that causes Alternaria Stem Canker

St – Resistance to the fungus that causes Grey Leaf Spot, Stemphylium solani.

Big Boy VFN shows resistance to Verticillium wilt, Fusarium wilt, and nematodes.    Tomato plant sellers in your area should stock the tomatoes with the resistance you need.  Look for the resistant cultivars in seed catalogs as well.

Don’t rely on planting disease resistance cultivars as your only line of defense against disease.  Good cultural practices like proper irrigation, mulching, soil building, fertilization and removal of diseased plants are examples of the integrated pest management (IPM) you should be using.

If you think your tomatoes have one of these diseases contact your local UGA Extension office for confirmation.  Georgia Home Grown Tomatoes is an excellent publication for tomato connoisseurs.

Happy Tomato Gardening!

 

This is My Heirloom Seed Story. What’s Yours?

My family hails from deep in the Appalachian Mountains. My mother’s ancestors came with Daniel Boone’s family through the Cumberland Gap and into what is now Breathitt County, Kentucky. My father’s family settled in Pike County, Kentucky, where he grew up at the back of church house holler. I am a McCoy from Hatfield and McCoy fame and like most people from Appalachia I have an heirloom bean seed story.

Beans in these mountains have been grown and handed down for centuries. Most Appalachian beans are cornstalk beans, meaning traditionally they were grown along with tall, open-pollinated corn. The tall corn stalks supported the long, bean vines. As time went on and hybrid corn stalks became shorter, people grew the beans on poles for support and they became “pole beans.”

As commercial beans became popular, large growers bred their beans for a tough outer shell or pod. The tougher shell meant that the beans could better stand mechanical harvest and handling. Appalachian beans are prized for their softer shell and full bean kernels. They have names like Lazy Wife Greasy Bean and Turkey Craw Bean. Eaten fresh or dried for winter dishes, they are family legacies. There are festivals honoring the Appalachian bean all across the mountains where seed swaps take center stage.

My bean seed was given to me by my Aunt Tillie. She received them from her mother who got them from her mother, and so on. My Jonah Beans are more of a bush bean than a cornstalk bean. In my north Georgia home, I can get three plantings of Jonah Beans each season. I generally grow enough for my family to enjoy and to put up a few canned jars. Of course I save seed year to year.

Jonah Beans in the May Garden

Beans are harvested, strings are removed (usually while sitting on the front porch) and prepared fresh. They are best cooked with a strip or two of bacon and a side of skillet cornbread. Happily, bush beans are a great addition to a community garden plot. They can also be used in school gardens with timely planting.

I am honored to be a keeper of this seed, of this mountain tradition. Planting, harvesting and preparing them is more than just growing beans. It is a way to connect with my heritage and to share that heritage with the next generation. If you are interested in Appalachian heirlooms Bill Best’s book Saving Seeds, Preserving Taste is a fantastic resource full of stories.

That is my heirloom seed story, what’s yours?

Soil Temperatures in Your Georgia Garden

Soil Temperatures in Your Georgia Garden

With the recent warm temperatures it is easy to be seduced into planting your summer crops now.   It is tempting to plant our vegetable transplants and seeds; we can’t wait for that first juicy tomato are a crunch pepper!  Be aware that soil temperatures are very important for success with your early summer plantings.

Soil Temperatures in Your Georgia Garden
Pepper Seedlings

Soil temperatures need to be 60-65 degrees F and rising at the 4 inch soil depth before you plant your summer crops.

If you install a transplant too early the roots won’t grow and the plant will just be sitting in the soil.  If we have a large amount of rain, which seems to be the norm this year, your new plant will just be sitting in wet soil.  This could mean early disease issues.

This morning the Ballground weather station, near my home, indicated a 4-inch soil temperature of 54.6 degrees F. In Griffin the 4-inch soil temperature was 56.8 degrees F while Valdosta reported 63.5 degrees F.

If the soil temperatures are not warm enough for seed germination, early seed plantings could rot.

The roots need to be actively growing to absorb water and nutrients.

If we plant and fertilizer summer vegetables too early we will be wasting fertilizer.  The plant roots simply can’t absorb it.  This fertilizer could get washed away, wasting your time and money. Also, this leached fertilizer could be problematic for our watersheds.

Determine your soil temperatures.

To determine your soil temperature at the 4 inch depth visit www.georgiaweather.net.  Click on the station nearest your garden.  Or, you can see a summary of soil temperatures across the state.

Soil Temperatures in Your Georgia Garden
Newly planted tomatoes. Waiting until the soil temperatures are warm enough is one step to success for your summer garden.

Remember the rule of thumb is play it safe and wait!

Happy Gardening!

What You Need to Know About Aeroponic Tower Systems

Schools with limited outdoor space and teachers who are uncomfortable with traditional agriculture are turning to aeroponic tower systems to grow food for the classroom. Cobb County Cooperative Extension office has installed one of the systems in their office and have had a few harvests of leafy greens and herbs. I recently talked with Daniel Price, a Cobb Extension program assistant, about the system.

How the Tower System Works
Aeroponics are a subset of the older hydroponics. They both are soilless systems that rely on a nutrient water blend. As a college student, a long time ago, I worked in a hydroponics lab. The nutrients flowed continually around the plant roots in an open system. We were continually concerned about bacteria and viruses infecting the nutrient system. Things have changed with the updated aeroponics.

Rockwool seed germination cells.

In aeroponic tower systems seeds are germinated in a special media called rockwool. Once the seedlings grow a few true leaves they are moved to the tower system. Cobb County’s tower example has 20 plant spaces with an outer ring for plant support.

The inside of the tower system. Look at those roots!

The nutrient water blend is housed in a 20-gallon drum at the bottom of the tower. The blend is rained on the plant roots for 15 minutes per hour. The system is enclosed which helps limit contamination of the nutrient blend. Plant lights surround the tower and are on a timer. Basically once the system is set-up everything is automatic until you are ready to harvest. Daniel says that it takes 2-3 weeks from lettuce seedlings to a full harvest.

The tower garden does not take up much space.

Issues to Consider
*This tower system cost approximately $1,000. This included the hardware, seedling starter kit, pH tester, pH buffer, and a start pack of nutrients.

*Leaks are sometimes a problem if the tower is not on very even ground.

*The pH needs to be routinely monitored but if it falls out of the recommended range, it is not too difficult to adjust.

*Algae growth is common around the rockwell plug and most experts do not think it is a problem. It just looks concerning.

*This system does not totally eliminate pest and disease issues.

Cobb Extension personnel are happy with the system. They have enjoyed the harvests and have not had any serious issues. Although they have only grown leafy greens and herbs at this point, the plan is to expand the plant selections. Daniel uses the tower as a teaching tool and has held several classes about aeroponics. Cobb Extension encourages anyone who wants to see the system at work to visit their office.

Thanks, Daniel, for showing me around the aeroponics system!

Happy Gardening!

March 19th Hands-on School Garden Day

Georgia Ag Awareness Week is March 19th through March 23rd. Monday, the 19th, is Hands-on School Gardening Day, a day to showcase Georgia school gardens. How will you celebrate? Use social media, the local paper, or even email proclamations to let your administration and community know about your school garden. Plan a special garden workday. Or, give tours of the garden. Definitely plan something special.

I first worked with a school garden in the mid-1990s. At that time the garden was a beautiful space that the teachers used for outdoor reading time or inspiration for writing assignments. The garden itself wasn’t used for instruction. Times have changed. School gardens are now used to teach geography, math, history, literature and science.

Atlanta Academy elevates their garden due to lack of available land.

Food plots are used to teach basic agriculture and nutrition through harvest taste tests. Younger students explore sensory gardens. Older students use produce from their school gardens to learn marketing and business skills as they model farmers market sales. These garden spaces have become a major part of our school curriculum.

Due West Elementary School in Cobb County uses the garden to teach math!

Research papers prove the benefits of learning in an outdoor environment. Georgia’s Department of Education recognizes this with the agriculture focus for science, technology, engineering, and math (STEM) certification. The verdict is in – school gardens are good for our students.

On March 19th as you celebrate Hands-on School Garden day, take a moment to recognize the hard work that you put into the program. Share your photos with us on our UGA Community and School Garden Facebook page. We want to celebrate with you!

Happy Ag Week 2018!

Indoor Seed Starting-Part Three

Now that your seeds have germinated the fun begins! When most of the seedlings have germinated and look strong, think about removing the top dome. You can do this gradually by placing it askew on the seed tray for a day or two before totally removing the top.

It is important to keep the light just above the seedlings and to move it as the seedlings grow. If the light is too far from the seedling, the seedling will become “leggy” as it grows towards the light.

Keep the light source close to the seedlings.

At this stage the seedlings are very fragile. When you need to add water, add it between the pellets. The flow of water can actually displace the seedling and/or damage the stem. Also watering from the bottom will help your roots grow longer. You want to avoid diseases such as damping off, so let the seedlings dry out before re-watering.

Fungus is your enemy here.

As the seedlings put on a few true leaves, they will outgrow the pellet and will need to be repotted in a larger pot with soil. After repotting you can keep them under the lights until the weather cooperates for transplanting in the garden.

As the seedlings get closer to that point, run your hand across the plants moving the stems slightly. The goal is to toughen the stems a bit so that they will be able to handle wind outdoors.

These seedlings are a bit leggy but they can still be good producers. Hardening-off is an important step.

When the weather is ready for transplanting you will need to harden off the transplants. If you take plants that have been living in a cozy, protected environment and move them into a place with full sun and wind they will suffer. You can avoid this by moving them out slowly. The first few days place them outside in the shade just for the day. Next, put them outside in the shade for the day and night. Then move them into full sun for a few hours. Finally, they are ready to be put in the ground. This type of hardening-off is the ideal way. You may not have all the time for all of these stages, but do the best you can. Your plants will reward you!

Happy Gardening!

Indoor Seed Starting – Part Two

All of this rain has me very excited about getting back to our seed starting project.

I have one note about seed starting media. If you choose to purchase bagged media for starting seeds indoors, do not choose something with fertilizer in the mix. This will be too strong for seedlings. There are plenty of bagged mixes specifically for seed starting so choose one of those.

We are ready to expand our pellets. Notice the seed pellets are fully expanded with no standing water:

Seed pellets are not too wet but moist all the way through.

Next, take a fork and open up the top a bit and fluff the media. I like to take this time to make sure that the moisture is uniform all the way through with no dry spots:

Fluff the planting media with a fork to ensure uniform moisture.

Now you are ready to plant your seeds. If you are mixing seed types in one tray, make sure that they will emerge and grow at about the same rate. I like to use plastic forceps to exactly place the seed where I want them. Some seeds, like lettuce and herbs, are very small and easily lost in the tray. Know how deeply to plant the seeds. Most of the ones you will probably plant just need to be lightly covered with the planting media.

Plastic forceps can be your best friend!

It is worth the effort to do some research on your seed types. For example, cilantro seeds don’t germinate easily when exposed directly to light. Also, there are some seeds that just do better planting directly into the soil, beans and corn are good examples.

At this point it is a great idea to label your seed tray. Sharpie markers on masking tape work well. The tape sticks to the tray but can be removed later. Do not be tempted to label the lid. You will be removing the lid later and you don’t want to forget the original orientation. Finally, put the lid on the tray, making sure it fits tightly.

Do not forget to label your seed trays.

Do not place your seed tray near a window and hope for the best. You will be disappointed. You will not get enough light for healthy seedlings and the temperature fluctuation at the window will be problematic.

Use a light system. The system does not have to be complicated. I have a light fixture with florescent bulbs attached to a structure with moveable chains. This setup was originally housed in a bathroom tub but it is now in my grown daughter’s bedroom. Very simple. You need the chain to move the light so it stays just above the seed tray. To produce robust seedlings you need the light no more than an inch or two above the tray. This will be imperative as the seeds germinate and grow.

If you are germinating seeds in a place that is reasonably warm you do not need a heating mat. Those were designed for outside greenhouses and places like Michigan. By using a heating mat when you don’t need one, you risk drying out your planting media.

So far this is pretty simple, right? If you have any questions or concerns you can comment or email me at beckygri@uga.edu. Send photos! Next week we will discuss seedling care.

Happy Seed Starting!

Indoor Seed Starting – Part One

Just flipping through one garden seed catalog I found 89 varieties of tomatoes, 21 varieties of cucumbers, 20 varieties of eggplant and 26 varieties of sweet peppers, including three types of lunchbox peppers. Compare that to the different types of vegetable plants that you would find at your big box retail store. Add some variety to your life and try starting your own seeds!

The rule of thumb is to start your warm-season seeds 6-8 weeks before planting time so over the next weeks we are going to explore indoor seed starting in-depth. For beginners, follow along with me as you start your first seeds. For seasoned seed-starting veterans, you may pick up a trick or two. I also encourage you to share your experience through the comments.

Let me begin by writing that there are many effective ways to start seeds indoors. I am going to share with you the way that I like to do it. I have been starting seeds indoors for decades and I have found a way that works best for me. You may find a different way that works best for you and that is terrific. I look forward to learning from you all as well.

To start, I like these re-useable plastic trays. They are easy to store and come in many sizes. I have friends who save their old plastic milk jugs and trim them down for seed starting; that works well for them.

These trays are easy to use for seed starting.

Any plastic trays MUST be disinfected before adding soil media and seed. I use a solution of 9-parts water to 1-part bleach. This step is important to eliminate any pathogens that have been overwintering on remaining soil particles. Starting with clean trays is an important step towards healthy seedlings. Don’t skip it.

These soil particles could hold pathogens. Disinfect those trays!

I like to use the peat moss discs for my planting media. As a bonus, the peat moss contains properties that discourage fungal growth. This helps prevent the disease damping off which is a real problem for seedlings.

The pellets expand with the addition of water.

These pellets are readily available and are easy to store. Add water and the pellets expand. I use warm water to create a favorable environment for the seeds. It is important here to not oversaturate the discs with too much water. Too dry is better for the seeds than too wet. Too wet means that the seeds could rot or disease will become a problem. You want the planting media to be just damp. If you can wring water out of the media, it is too wet. If this happens you can let the discs sit outside the tray for a few hours so that they can dry out a bit. You will get the hang of how much is too much as you practice.

Okay, gather your seed starting equipment, and play around with the pellets. Next week we will talk about planting the seeds.

Happy Gardening!