On Tuesday, August 6th at 7pm, the Bartow County Extension office will be hosting a free seminar on “Troubleshooting Vegetable Garden Problems.”  This is a great opportunity for backyard gardeners and local farmers to bring plant samples for diagnosis and discuss common vegetable problems this season.  We will also have several door prizes to give away during the seminar!  Please call the extension office at 770-387-5142 to let us know you’re coming.

There’s much debate among County Extension agents about the most common garden problems that we encounter on the job. The majority would agree that the number one issue is frequent water application to gardens, especially in our Georgia red clay soils.  Clay soils have the highest water holding capacity of any soil in the world.  As a result, it’s very easy to “overwater” plants that are growing in clay soil, which takes longer to dry out than other soil types.

I cringe every time a client tells me they water their garden every day.  Even watering lightly every day is not a good thing, since only the surface of the soil gets wet and the roots remain shallow or stunted.  Shallow water will evaporate from the soil before the plants can absorb it.  What you want to do is encourage deeper roots by forcing them to seek out the water in the subsoil.

The other extreme of watering excessively every day invites root rot and disease.  Roots actually need oxygen to grow and stay healthy.  If the soil remains saturated and never has a chance to dry out for a few days, then the roots will die from a lack of oxygen.  Ironically, when roots start to die, the plant will actually start to wilt because the dying roots are unable to absorb water.  This creates a vicious cycle were people assume they need to water their “wilted” garden more.

The proper way to water a garden with clay soil is more deeply and less frequently.  The rule of thumb is to apply about one-inch of water per week.  If we get an inch of rain, you shouldn’t water your garden for at least a week.  If we get a half-inch of rain and no rain is in the forecast, then you should water the garden the other half-inch a few days after the last rain event.  The best way to “gauge” how much water you’re applying with an overhead sprinkler is with a rain gauge.  Turn on the sprinkler and time how long it takes to apply a quarter or half-inch of water.  Adjust the amount you need to apply according to the weather.

If you use an overhead sprinkler for irrigation, be sure to only water early in the morning before 10am so that the leaves will dry more quickly as the sun rises.  Watering at night or late in the evening will increase the chances of many disease problems.  You might also want to buy an automatic timer to shut off the water.  These are available at most garden centers and can be attached to the hose bib.  I like to set the timer on my garden before going to work in the morning and not have to worry about turning it off.  A simple mechanical timer usually costs between $10 and $20, a reasonable amount given the convenience they provide.

If you’re hand-watering your vegetables with a hose, time how long it takes to fill up a 5-gallon bucket of water.  Six gallons of water per 10 square feet soaks the soil about the same as 1” inch of rain.  This will vary depending on your water pressure, hose size, and nozzle that you have on your hose.  If it takes 30 seconds to fill a 5-gallon bucket, then you can count to 30 while you water each tomato plant in your garden.  This is all the water that plant will need for about a week.

Invest in an extended watering wand that allows you to place the water directly on the roots rather than spraying the leaves.  Keeping the leaves dry will significantly reduce the chances of many leaf diseases.  An ounce of prevention is worth a pound of cure (or pesticides).  Soaker hoses and drip irrigation systems can also be used to efficiently place the water on the plants’ roots rather than the leaves.

For more information on specific insects, diseases, and other vegetable disorders, join us for our upcoming seminar this week.  We’ll be able to discuss more strategies to manage and avoid common vegetable problems through techniques such as crop rotation, weed control, resistant varieties, proper spacing, soil testing, sanitation, chemical control, soil temperature and planting dates.  Be sure to bag a bug, weed, or disease sample and bring it to the seminar!