Flooding in the Community Garden

Many of our community gardens are located in floodplain areas (which is why the community is not using that land for something else!) or near creeks or rivers. Recent weather events may have left parts of your community garden flooded. UGA food safety experts ask us to think the safety of our produce from flood waters. Farmers have to think about this on a large level, but it is still a concern for us. Experts from UGA released important harvest information for farmers ahead of this hurricane. Also, the FDA has guidance for flood affected produce.

If a flooding creek encroached on your garden what did that water bring with it? Possibly contamination from pathogens harmful to humans. What about chemical hazards from another site that washed into your garden? These could be serious. If flooding did occur in your garden, I advise you to speak with your local UGA Extension agent for advice from a food safety perspective.

Thinking of the gardeners and farmers in the path of the storm today.

Thoughts on Plant Disease in the Georgia Garden

Every year seems to bring a new set of challenges for the Georgia gardener. Some years the drought leaves our gardens in the dust and some years it never seems to dry out. Some years we break record heat waves and some years fall comes early. However, plant disease never seems to give us a break. As we try and coax healthy cool-season crops out of warm soil I thought it might be nice to take a look at some disease facts so we can come up with strategies to help ourselves.

Fact #1: Healthy plants can withstand disease better than stressed plants. Knowing what healthy plants look like (is that mottling part of the normal leaf or could it be a virus?), what your plants need in the way of fertility and water, and what conditions those plants need to thrive will go a long way in managing disease. If your plants need full sun, plant in full sun. Shade will stress your plants and open up the possibility for disease. Have your soil tested for fertility and use the results to meet the needs of your plants. Take away: Strive for healthy plants

Rust disease on a bean plant leaf

Fact #2: Most of our disease-causing agents are fungi. We do battle some bacteria and some viral diseases but overwhelmingly fungi are our problem. Most fungi need a wet environment. You probably notice during rainy periods disease symptoms seem to magically appear. Community gardeners tend to plant our plots as full as possible limiting air circulation around the plants. Moisture stays on the leaves creating a perfect environment for pathogens. Take away: Limit overhead watering as much as possible. Make sure your plants have adequate air flow around them.

Fact #3: Often pathogens overwinter in garden debris. Many times fungal survival structures, like spores and mycelia, will last for months(years) in organic matter, leaves, and garden debris creating an environment for a reinfection during the next planting cycle. Take away: Clean your garden plots after every season.

Powder mildew fungal spores under a microscope.

Fact #4: Most fungicides are used as preventatives and not as a cure for disease. Once a plant has been infected it is hard to cure that plant. The pathogen is already present, has done damage and gardeners cannot rely on fungicides to fix the problem. Take away: Plan ahead for disease management.

Fact #5: Some pathogens will infect many types of plants but many pathogens have a narrow plant host range. Rusts (Uromyeces spp.) are common among bean plants and powdery mildew (Oidium spp.) always seems to find all types of squash. Take away: Know what diseases normally affect the plants you have in your garden. Learn to recognize the pathogen signs and symptoms. Use your local Extension office to help identify the diseases that plague you. Your agent can also help you devise a plan of disease management.

Upcoming Events for Georgia Community & School Gardeners

Fall is a busy time for gardeners and this fall will be especially busy with several exciting conferences scheduled in Georgia.

September 13th – 16th the American Community Gardening Association will have its 39th annual conference in Atlanta. Events will take place all across Atlanta with the hub of presentations at the Georgia International Convention Center in College Park. The theme is “Tending to the Beloved Community.” There are 36 presentations scheduled, tours of Atlanta area gardens, and a gala at the Atlanta Botanical Gardens. Registration is open. The conference schedule features several notable speakers including Georgia Department of Agriculture Commissioner Gary Black. I have heard him speak several times and he always delivers an entertaining and inspiring presentation.

September 22nd is the Monarchs Across Georgia Pollinator Symposium at the Monastary of the Holy Spirit in Conyers. This event will have fantastic speakers, nature walks, exhibitors and demonstrations. Many of you all feature pollinator spaces in your gardens and this would be a worthwhile day for you! Registration is open.

October 19th – 20th the Council of Outdoor Learning is holding their Outdoor Learning Symposium. It will be held at the Garden School in Marietta, just off the square. The Council of Outdoor Learning, an initiative of the Environmental Education Alliance of Georgia (EEA), is a coalition of organizations and individuals who share an interest in the design, development, maintenance, use, and longevity of outdoor classrooms. COOL serves teachers, parents, principals, and community volunteers as a resource link, providing up-to-date training and information to those interested in building and using outdoor classrooms. This will be a fantastic event for school gardeners and community gardeners who are interested in finding additional ways to use their space.

All three of these events are worth your consideration. Don’t forget to check with your local UGA Extension office for fall classes on cool-season gardening.

Happy Conferencing!

Three Rules of Weeding in Your Georgia Garden

Weeding in Your Georgia Garden

All of Georgia has seen a large amount of rain this summer. Rain is great for our crops and also great for weeds and if you have gotten lazy with the summer heat your plots may have more weeds than crop. You are not alone! This may be a great time to review best management practices for weed control.

Weeds can be a big problem in a community or school garden.  A very big problem.  Knowing how to weed correctly will make this job less of a headache.   An informal poll was taken and we asked experienced gardeners to give their top three rules of weeding and we present them here:

Rule #1:  Get the roots out.

If you just remove the leaves above ground chances are the weeds will come back and you will need to perform the same weeding chore over again.  Many perennial weeds grow from underground roots and tubers.  Those need to be removed as well.

 

Weeding in Your Georgia Garden
Get those roots out!

Rule #2:  Remove the weeds before they make seeds.

If your weeds are allowed to flower and make seeds your work will get much harder.  Weed plants can make an incredible amount of seeds.  For example, common chickweed can produce 800 seeds per plant.  Dandelion flowers can make 40-100 seeds.   Crabgrass can produce 53,000 seeds per plant and pigweed can produce over 200,000 seeds per plant.  Don’t let those weeds flower!

Weeding in Your Georgia Garden
You don’t want this!

Rule #3:  Don’t let weeding get out of hand.

If you don’t routinely remove weeds you could be looking at a plot of weeds that seems overwhelming to tend.  Your vegetable production will suffer as the weeds take up the water, nutrients, and space that should be used for your plants.  And, it will take a lot of initiative to start the long process of taking back that space from the weeds.

Weeding in Your Georgia Garden
Don’t let weeds take over your community or school garden plot.

Knowing what weeds you have could be helpful in coming up with a long-term weed management plan.  Your local UGA Extension agent can help with weed plant identification and help you find strategies to minimize weed issues.

Happy Gardening!

 

A Country of Gardening Immigrants

Happy 4th of July week!   I hope your celebration will a good one full of fresh Georgia tomatoes, onions, watermelons….

As we think about the birthday of our country and how Americans celebrate there is always some type of food involved.  And, depending on your cultural background it could include extra garlic, long beans, or tomatillos.  The world is our garden and we have always been a country of immigrants.

A County of Gardening Immigrants
Chinese Long Beans

A Garden is Common Ground

Across our country experienced gardeners are welcoming immigrants and refugees from all over to the United States in a garden setting.  A garden is common ground.  There may be language barriers but we can all “talk” seed, soil, and water.

Having the privledge of working with some of these gardens it is exciting as cultures are shared through the growing of food.  Gardeners from Somalia are interested to see what the gardeners from Burma are growing.  Gardeners from Kenya are poking their heads in the Syrian’s garden to see what is coming up there.  Our American melting pot is alive and well in the garden.

People especially seem to enjoy growing foods from their homeland and their childhood.  This is true even within the United States.  Many a displaced Southerner has taken the family collard green seeds when being transferred to “the North”.  Year after year, I grow family bean seeds brought down from the hills of Kentucky to Georgia.  So, it is to be expected that our collective palate would be enriched by foods brought with immigrants from other countries.

A Diverse Dinner Plate

If you are fortunate enough to be invited to a pot-luck dinner at one of these gardens, it is an experience worthy of a 5-star restaurant rating.  And, it will make you truly thankful for our county and all of its diversity.

A County of Gardening Immigrants
North Fulton Extension Garden

A special “Thank You” goes out to a local food partner Global Growers who does such tremendous work with these gardeners in Georgia.  And to gardens like the International Garden of Many Colors in California, the Fresh International Garden in Anchorage, Alaska and the North Fulton Extension Garden in Sandy Springs, Georgia.

Happy Birthday, America!

Avoid Heat Stress in the Georgia Community Garden

I have gotten some requests to repost this information about heat stress. It is definitely summer in Georgia so we all need to take care.

Summer heat can be dangerous, especially with the heat and humidity we are experiencing this summer.   We went to a professional to get tips on how to stay safe in a hot, humid Georgia garden.

Heat Stress in the Georgia Community Garden
The Weather Channel knows heat!

Millard Griffin is a Certified Safety Professional with Environmental Resources Management (ERM).  He has vast experience dealing with heat related issues on environmental projects from the Florida Everglades to the Gulf Coast of Louisiana.  He knows heat and humidity.

Heat stress is a real concern for those working in the garden.  Especially for those of us who aren’t out there every day.  Heat stress is defined as any situation where the human body is unable to cool itself by sweating.  This can lead to several conditions including heat rash, heat cramps, heat exhaustion, and heat stroke (a medical emergency).

Tips to Prevent Heat Stress

To prevent these conditions Mr. Griffin gives us the following tips:

  • Acclimatize to the heat.  Work a limited amount of time outdoors and gradually increase your amount of time in the heat.
  • Avoid the high heat periods of the day.  Get your work done early in the morning or late in the day.   Avoid the hours between 2 and 6 as the heat loads are typically higher during these hours.
  • Take frequent breaks in a cool area.  Taking breaks in an air conditioned area is preferable but, a shady area will work.
  • Limit exposure to direct sunlight when possible.  Plan your workday to take advantage of shaded areas.
  • Drink plenty of water.  Take a water break at least every hour, drinking cool water.  Also, drink water before working in the garden.  Hydration is key.
  • Avoid caffeinated beverages and alcohol.  These are diuretics and cause your body to lose water.
  • Wear light colored, loose fitting clothing and a hat.  Certainly use sunscreen to protect against UV rays on all exposed skin.
Heat Stress in the Georgia Community Garden
Work in shade whenever possible.

Monitor Yourself

It is preferable to work with another gardener so you can monitor each other.  If you notice extreme sweating, dizziness, nausea, or muscle cramps STOP WORKING.   Head indoors, hydrate and cool down.

Certain people are more susceptible to heat stress – the elderly, children, pregnant women, and people who have just moved here from a cooler climate.  Certain medications can also make someone more prone to heat stress.   Mr. Griffin recommends checking with your doctor if you take medications.

Knowing this information will help keep you safe in the Georgia summer heat and make your gardening experience a more pleasurable one.

Remember georgiaweather.net is a wonderful resource for weather information.

Thanks Mr. Griffin for the tips!  Stay safe and

Happy Gardening!

 

 

Insect Scouting is an Important Part of Vegetable Growing

Whether you work a large family farm, a home vegetable garden, or a 4’X8’ community garden vegetable plot, routine scouting for insects should be an important part of your vegetable growing plan. Insect pests can be a costly problem on vegetables and the lifecycles of some of our insect pests are so short that missing a week of scouting can lead to damaged crops and increased pest numbers.

Scouting involves carefully and deliberately walking though the garden looking for insects on a routine basis. Inspect the leaves and fruits/vegetables. Look on the undersides of leaves and on the stem. Evidence of boring insects can be seen on the plant stem while insect eggs are often deposited on the leaf undersides. If you are unsure of an insect identification, contact your local UGA Cooperative Extension agent for assistance. Do not automatically reach for an insecticide!

Insect eggs are easily removed. Simply remove the entire leaf and fold the leaf over on itself and smash the eggs. Or, if you want to preserve the leaf, use sticky tape to remove the eggs. Place tape on top of the egg mass and gently pull removing the eggs. Fold the tape on itself and smash the eggs.

Squash bug eggs are easy to remove.

Eggs like these are easy to miss if you don’t routinely scout your garden! Dealing with squash bug eggs is easier than managing the 30+ pest insects that could mature from these eggs. A helpful video goes through the easy steps.

Learning about the insects that are common pests for the food crops you are growing can be very helpful. Leaf-footed bugs (Leptoglossus spp.) are a problem for tomatoes while squash bugs are pests in cucumbers, squash and pumpkins. Aphids (Aphidoidea superfamily) are a common problem especially when plants are full of liquid, after a rain, or when plants are growing quickly. Mexican bean beetles (Epilachna varivestis) can easily destroy a bean crop but these insects have been mistaken for beneficial lady beetles.

Pest Mexican bean beetles can be mistaken for beneficial lady beetles.

It is estimated that only 3% of insects are pests so the insects you find in your garden are not always problematic. Don’t assume every insect you find is a “bad bug!” Take time to learn about beneficial insects such as assassin bugs, parasitic wasps, and lady beetles. These can be tremendous allies in your garden. Often these insects need floral resources and the plants you have added to attract pollinators will also help other beneficial insects.

The copper colored ovals in the photo below are aphid mummies. A helpful parasitic wasp laid an egg inside an aphid pest (green insect below). As the egg hatched the resulting larva consumed the aphid insides for nutrition. When the wasp matured it emerged from the aphid leaving the empty shell, aphid mummy, behind. Adult wasps will be looking for some nectar so your pollinator garden will be useful here.

Aphid mummies mean that parasitic wasps are working for you.

Scouting is just one tool of an integrated pest management (IPM) program. Other tools include:

¥ Altering planting time to miss large insect populations
¥ Using trap crops
¥ Starting with healthy soil
¥ Keeping the garden clean of debris
¥ Hand-pulling weeds
¥ Creating habitat for beneficial insects and pollinators
¥ Watering wisely
¥ Using plants that are proven to do well in your area

Happy Gardening!

Tomato Hornworms and Parasitic Wasps

Tomato hornworms (Manduca quinquemaculata) are a serious problem for tomato growers. These caterpillars have a large appetite and can quickly defoliate a tomato plant. If you find hornworms in your tomatoes, simply pick them off and drop them in soapy water. However, if you find a hornworm with white oblong obtrusions, leave it!

The white obtrusions are actually the cocoons of a parasitic wasp. A female wasp has laid her eggs under the skin of that hornworm. As the eggs hatch the larvae actually feed on the hornworm insides. The larvae eat their way out of the caterpillar and spin the cocoons you see. Eventually adult wasps will emerge from the cocoons and the weakened hornworm will die.

Photo credit: Texas A&M

The hope is that the emerging wasps will find other tomato hornworms to parasitize and you will have managed that pest. There are some generalist parasitic wasps that will provide that service for you. There is a braconid wasp, Cotesia congregates, that specifically looks for tomato hornworms. This small wasp has clear wings and as an adult they are nectar feeders. To persuade the wasps to stay in your garden you will need to have flowers. The small braconid wasps are attracted to small flowers like yarrow and small asters.

Instead of reaching for an insecticide for tomato hornworms encourage the ecosystem to assist you in managing that pest!

Happy Gardening!

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!