Stu Campbell - How to Mulch: Save Water, Feed the Soil, and Suppress Weeds. A Storey BASICS®Title

If the mulch is deep, weed seedlings that sprout in darkness will wither away.

If the mulch is too thin, some weed will poke through. Even then, they are easy to spot and easy to pull.

Simply stated, mulch is insulation. It can keep the soil around your plants roots cooler during hot days and warmer during cool nights.

In winter, mulch works to prevent soil from rapidly freezing and thawing and so prevents the soil from heaving, which causes root damage to your plants. Although mulch may not prevent the soil from freezing, it can prevent freezing from happening overnight. Its best to apply winter mulch in late fall, after the ground has frozen. Come springs warm weather, removing the mulch allows plants to start sprouting new growth.

Mulch also is useful for controlling soil temperatures in summer. Applied in the spring after the soil starts to warm up, mulch should remain in place for the majority of the growing season. Extremely high soil temperatures can hinder root growth and damage some shallow-rooted plants. During the long, hot days of summer, mulch can reduce soil temperature by as much as 10F.

Some plants, such as tomatoes, eggplants, and peppers, thrive in heat. Dark mulches, such as black or red plastic, warm the soil and have been shown to increase fruit yields for plants such as these (see ).

Mulch absorbs the impact of falling raindrops and, as a result, prevents soil compaction and crusting. Water penetrates through loose, granulated soil but runs off hard, compacted earth. Mulch controls erosion by slowing water runoff and wind speed over soil.

Many organic mulches, such as shredded leaves and bark chips, add organic material to soil as they decompose. This material enhances soil structure, which then leads to all sorts of great things, such as improved air, water, and nutrient movement throughout the soil.

In addition, mulch encourages earthworms to proliferate. Worms further aerate the soil and release nutrients in the form of their waste, called castings. Mulch also stimulates increased microbial activity in the soil. Certain bacteria are every bit as important as worms for maintaining healthy soil. Microbes break down organic matter rapidly, which makes nutrients available to plant roots sooner.

Mulching supports earthworms. Earthworms create spaces for air and water movement in soil under mulch, and their castings include nutrients from digested mulch

Mulch Helps Grow Healthy Plants

Mulched plants are less diseased and more uniform than those without mulch. One reason for this is that mulching prevents fruits, flowers, and other plant parts from being splashed by mud and water. Besides causing unsightly spots and rot, splashing can carry soilborne diseases. Mulch protects ripening vegetables, such as tomatoes, melons, pumpkins, and squash, from direct contact with the soil. That means fewer bad spots, rotten places, and mold.

Mulches help control harmful soil nematodes and fungi and can also reduce insect pest populations and some diseases that they spread. Basically, mulching helps reduce plant stress. Healthy, strong plants have the energy and resources to better protect themselves against insects and other pests.

Organic Mulch Increases Soil Nutrients

While not dependable as a primary plant food, organic mulch can contribute nitrogen, potassium, phosphorus, and several trace elements to the soil. The amount of nutrients available from mulch depends on the mulchs age, type, and duration of weathering.