University of Illinois
Summer watering tips for the vegetable garden

 

[June 18, 2019] 

With summer heat approaching, University of Illinois Extension reminds gardeners to think about watering.

All plants need water to survive. Some plants can tolerate dry conditions, but gardeners should investigate the requirements of plants before letting them dry out or providing too much water.

“A soil test is a valuable resource not only for nutrient levels,” says Illinois Extension horticulture educator Andrew Holsinger. “A soil test can measure cation exchange capacity, which indicates the soil’s water and nutrient holding capacity. Typically, the higher the cation exchange capacity, the higher the holding capacity because of the increased clay content.”

He adds that a low value for cation exchange capacity means that soil needs to be watered more frequently.

When using automatic irrigation, consider the type of emitter based on soil type. Focusing the water directly on the desired plant will help avoid watering undesirable weeds.

“Plants have critical stages when they need water during their development,” Holsinger says.

Critical periods of watering for vegetables:

• Bean, lima – Pollination and pod development

• Bean, snap – Pod enlargement

• Broccoli – Head development

• Cabbage – Head development

• Carrot – Root enlargement

• Cauliflower – Head development

• Corn, sweet – Silking, tasseling, and ear development

• Cucumber – Flowering and fruit development

• Eggplant – Uniform supply from flowering through harvest

• Melon – Fruit set and early development

• Onion, dry – Bulb enlargement

• Pea – Flowering and seed enlargement

• Pepper – Uniform supply from flowering through harvest

• Potato – Tuber set and tuber enlargement

• Radish – Root enlargement

• Squash, summer – Bud development and flowering

• Tomato – Uniform supply from flowering through harvest

• Turnip – Root enlargement

Automatic timers can be a great aid in watering but Holsinger reminds gardeners to adjust timers when rainfall is received.

“Following good cultural practices like proper irrigation both in quality and quantity of water is important,” he says. “Contaminated water can carry pathogens that, when applied to vegetables, can cause illness.”

Container plants will often need to be watered more frequently in the summer. Avoid using native soil in containers because of their poor drainage. Instead, use a soil-free mix that promotes a well-drained root environment.

According to Holsinger, “It is important to provide drainage holes in containers as appropriate for the plant’s needs. And remember not to overwater.”

[Andrew Holsinger, Horticulture Educator, University of Illinois Extension]