How to Use Mulching and Avoid Overwatering in Summer Vegetable Gardens

LINCOLN, Neb. — It is almost summer and vegetable gardens are starting to grow. University of Nebraska-Lincoln extension educators Sarah Browning and Kelly Feehan have some advice on garden weed control and how to avoid overwatering.

There are several benefits to mulching, Browning said.

Mulch reduces light that reaches weed seeds, making them less likely to germinate. If they do germinate, mulch allows for easier removal, reducing time spent weeding.

Having a garden covered with mulch conserves water by reducing evaporation from the soil surface, so the gardener does not have to water as frequently. Produce grown in a garden with mulch is cleaner because mulch keeps dirt off fruits and vegetables.

There are several different types of mulch.

“Straw is great mulch for the vegetable garden,” Browning said.

Straw can be used in conjunction with six or seven layers of newspaper. Plant vegetables through holes cut in the newspaper and cover with straw.

It is important to make sure that the straw is clean, as it is known to carry weed seeds.

There are many colors of plastic mulch available, Browning said.

Black and brown plastic mulches are traditional colors. Red plastic mulch has been found to increase tomato production by 12-20 percent and plastic mulches with a metal reflective surface have been found to repel aphids.

Wood chips work well around perennial vegetables like rhubarb and asparagus.

Mulch helps conserve soil moisture, but too much water can be a bad thing. It is important to manage how often gardens are watered.

“It’s actually a fairly common problem,” Feehan said. “Plants do not grow well in a saturated or continuously wet soil.”

Feehan said that plants need an equal amount of oxygen and water in the soil.

If the soil is clay-like, signs of overwatering include water running off onto streets or sidewalks.

“Overwatering is a waste of water and it is harmful to plants,” Feehan said.

Too much water can cause plants to turn yellow or wilt and cause their roots to rot.

Gardens should only be watered if the soil is dry. Automatic irrigation systems should be monitored so that they do not come on when it is raining.

“Know your irrigation systems,” Feehan said. “Don’t just set them and forget them.”