News Article

Lessons from my vegetable garden

University of Illinois Extension
11-15-2018

squash bugs

URBANA, Ill. – This summer marked the fifth year for Jennifer Fishburn’s vegetable garden’s current location. “Besides the okra, this was the least amount of produce that I have ever harvested,” says the University of Illinois Extension horticulture educator. “Squash bugs killed the squash plants, tomato plants succumbed to disease and lack of fertility, and rabbits ate all the green bean plants.” 

So what is a gardener to do? Some conditions are out of a gardener’s control, such as temperature and the timing and amount of rainfall. However, there are steps that can be taken to have a more productive vegetable garden. 

Plants need an optimum pH for good growth. For example, most vegetable plants grow best in soil with a pH range of 6.0 to 7.0. A soil test will determine the current levels of phosphorus, potassium, organic matter, other important minerals, and pH. Soil test results can help gardeners determine the amount of fertilizer or organic matter to apply to the soil. Vegetable gardeners should get their soil tested every three years, according to Fishburn. 

“Soil can be collected for a soil test when soil temperatures are above 50 degrees Fahrenheit. Late summer or fall is the best time,” Fishburn says. “Take several random soil samples in your garden at 4 to 6-inches deep. Mix samples together and put about 2 cups in a bag for testing.” For a list of labs, visit the University of Illinois Extension soil testing lab website at http://extension.illinois.edu/soiltest.

Tomatoes grow best in a well-drained, loamy soil with a pH of 6.5 to 6.8. “Tomatoes are heavy feeders, but don’t overdo it as too much fertilizer is as problematic as too little fertilizer,” Fishburn says. “Follow soil testing result suggestions for applying fertilizer.”

Fishburn says many gardeners dealt with tomato diseases this year. Gardeners who experienced tomato diseases should sanitize cages and stakes with a nine-part water to one-part bleach solution. Purchasing disease-resistant cultivars is a good idea, but does not guarantee immunity to a disease. Space plants correctly to allow for good air circulation. If possible, rotate the planting location on a three- to five-year rotation.

Squash bugs prefer to feed on squash and pumpkins but will also eat other members of this plant family, such as cucumbers and melons. Adults suck the sap out of leaves, disrupting the flow of water and nutrients causing a yellow spot that eventually turns brown. They also can feed on fruit. Adult squash bugs survive the winter in sheltered places such as under plant debris. In June, females begin laying their eggs. Eggs hatch in about 10 days and mature in about four weeks. 

The key to squash bug management is early detection of egg cases and nymphs, Fishburn says. Adult bugs are difficult to kill. Cultural controls include maintaining healthy plants through proper fertilization and watering.  Mechanical controls include crushing eggs that are attached to the underside and stems of leaves. You can also trap squash bugs by laying out boards. At night, the bugs will hide under the boards and can be disposed of in the morning. Insecticides are another option. They should be applied in early morning or at dusk, to minimize impact on pollinators. Be sure to spray underneath leaves, as this is where most squash bugs feed.

For vegetable gardeners, the best approach to keep rabbits from eating young plants is to exclude them from the garden with a fence. Wire poultry netting with 1-inch holes works well to protect plants from rabbits. Bury the bottom edge of the fence about 4 inches below ground.

“Now it’s your turn. Have you thought about what went well and not so well for your vegetable garden? My steps to growing a more successful vegetable garden are to get the soil tested, add organic matter, install poultry netting around the rows of green beans, and fertilize and water tomato plants,” Fishburn concludes.

Jennifer Fishburn fishburn@illinois.edu