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CHAPTER 1

PART ONE

The Whys and Whats of Mulching

Once thought of primarily for vegetable gardens, mulch has come a long way. It's now recognized as an essential ingredient for more beautiful and easier-to-maintain flower beds and landscape plantings of all kinds. And mulch has many important environmental benefits as well, one of the most important of which is water conservation.

Many kinds of materials can be used for mulching. The mulch materials you choose for your vegetable garden can be practical but not necessarily beautiful. On the other hand, you'll find dozens of mulching choices for use around your landscape plantings and flower beds, where the mulch itself can be an important feature of the overall design.

There is no one "right" way to mulch. There are good ways, and there are not-so-good ways. In addition to providing solutions to common mulching concerns, this book offers suggestions about ways to mulch your gardens to make them happier, healthier, and more rewarding.

The Benefits of Mulching

From improving soil to suppressing weeds, mulching brings many benefits to your gardens and landscaped areas. You will also be able to walk around in your garden on rainy days and not have 3 inches of mud stuck to the soles of your shoes. The following list covers mulching's essential benefits.

Mulch Retains Moisture

Mulch's ability to conserve soil moisture has long been documented (up to 50 percent in some studies). This water-conserving value can't be overemphasized, especially during times of water restrictions, shortages, and drought conditions.

Mulch retains moisture.Mulch keeps soil from drying out by preventing evaporation of dew and moisture that is drawn up from the subsoil.

Mulch helps prevent water in the soil from evaporating. Some impervious mulches, such as black plastic, do not allow air or water to pass into or out of the soil. Permeability is something to keep in mind when selecting a type of mulch (see How to Choose a Mulch).

Mulch Suppresses Weeds

Mulching can practically eliminate the need for weeding and cultivating. There are a few catches, however.

First, the mulch itself must be weed free. If it is not, you will end up introducing a whole new pesky crop of weeds.

Second, mulch must be deep enough to prevent existing weed seeds from taking root. Weed seedlings need light to grow. If mulch is applied too thinly, weeds may be able to poke through.

Finally, mulches won't smother all weeds. Some particularly hearty weeds have the fortitude to push through just about any barrier. In a well-mulched bed, though, these intruders should be easy to spot and even more easily plucked.

Using Mulch to Keep Down Weeds

Mulch Insulates from Heat and Cold

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. It's best to apply winter mulch in late fall, after the ground has frozen. Come spring's 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 10°F.

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 Mulching Vegetables).

Mulch Controls Erosion and Improves Soil

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.

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 mulch's age, type, and duration of weathering.

Mulch Is Environmentally Beneficial

Using mulches for weed control helps reduce your dependence on chemical herbicides. The fewer chemicals you use, the lower the risk of groundwater contamination, general exposure to toxins, and accidental poisonings.

Mulching is an excellent way to reduce and recycle yard waste. Dead plants (that are not diseased or insect-infested), leaves, grass clippings, and old newspapers are fair game for the mulch pile. Even shredded or chopped woody materials can be converted into mulch. However, be sure not to add poison ivy, poison sumac, or poison oak to your mulch.

Mulch Is Attractive

Many people mulch their garden just because they like the way it looks. Mulch makes a garden look a little better or neater. It adds color and texture to the landscape, and covering ornamental beds with shredded bark or hardwood gives a professional touch.

Some Drawbacks to Mulching

There are some key issues to consider when deciding how to mulch. But with most problems come solutions. Let's look at these considerations one by one.

Controls but Doesn't Eliminate Weeds

It's true that mulches can't smother every weed. Robust perennial weeds have been known to push up through straw, wood chips, and black plastic. They've even been known to break through concrete sidewalks!

Solution. Mulching makes it easier to pull out weeds. Remember, mulching is not meant to eliminate all your gardening chores. It simply makes them easier.

May Cause Nitrogen Deficiencies

Any fresh, light-colored, and unweathered organic mulch will "steal" nitrogen from plants during the earliest stages of decomposition. This happens because the microbes breaking down the material use soil nitrogen. Wood-based products, such as sawdust or wood chips, are routinely condemned for doing this, but hay, straw, and leaves also can tie up nitrogen. Eventually, though, these materials will add nutrients back into the soil as they decay.

Solution. To deal with the temporary nitrogen shortage, supplement your garden with additional nitrogen. Try cottonseed meal, alfalfa meal, or a synthetic source such as calcium nitrate or urea.

May Hinder Water Penetration

The case against plastic mulch has always been its inability to let rainwater through to the soil and, ultimately, to the plant roots. The same can be said for some organic types of mulch, such as leaves, if they get matted down.

Solution. If you decide to use plastics, be sure to moisten the ground thoroughly before laying down the material. Place the plastic down and make slits or holes in the vicinity of your plants to allow for watering. Doing so will expose those areas to weed growth, so you may have to pull a couple of stragglers now and then.

As for matted leaves, chopping them beforehand is the best way to prevent matting. For other compacted organic mulches, turn or loosen them occasionally to allow water to reach the soil and plant roots.

Blocks Airflow

Blocking airflow is another shortcoming associated with plastic, but even organic mulches applied too deeply or repeatedly can restrict air movement into the soil. Roots need air to breathe. Many beneficial microorganisms that break down nutrients absorbed by roots also need air to live.

Solution. It's a good practice to get in there and stir things up occasionally. Loosen the crust with a hoe or rake. If you plan on supplementing your mulch because it has lost some of its color and appeal, be careful not to overdo it. There is no need to add 4 inches of mulch when only 1 inch is needed to freshen the appearance.

Provides Breeding Ground for Insects, Slugs, and Snails

You will find an increase in the slug and snail populations when you use mulches, particularly in years with a wet spring. These wet, slimy creatures love the dark, damp areas under a mulch, whether it's organic or black plastic.

Solution. A light dusting of wood ashes, sharp sand, or crushed shells on the ground at the base of plants works well to prevent these pests from feasting on your plants. Slugs and snails don't like to crawl over materials abrasive to their underbellies. These deterrents should be reapplied regularly because they deteriorate with rainfall. Drowning slugs in shallow pans of beer is another option for managing them.

Can Be Unpleasant and Difficult to Handle

Selecting and applying the wrong mulch for your situation can be a big headache. On the other hand, applying an appropriate mulch early in the growing season prevents a lot of problems. For example, a winter mulch application may keep perennials from perishing in the freeze/thaw cycle. If your mulching repertoire is wide enough to allow you to choose the right place for the right mulch at the right time, you can enhance your garden's attractiveness and productivity with a minimum of effort, time, and money.

Solution. If you don't have time or just aren't up to the work of mulching, there are garden care professionals who will gladly deliver and apply mulch to your ornamental beds. For vegetable and small gardens, consider hiring a teenager or local agricultural student to give you a hand. The cost of this help will be minimal compared to the labor of weeding and watering in the summer heat!

May Attract Rodents

Mice and other rodents may take up residence in the warmth and protection of a thick mulch during the cold winter months. As food supplies dwindle, they may elect to gnaw on your favorite fruit tree.

Solution. To prevent rodents from feeding on the roots and trunks of your trees or shrubs, never apply an organic mulch all the way up against the base of the plants. Leave 6 to 12 inches of space between the mulch and the tree or shrub. If the mice are going to feed on your tree, they'll have to come out in the cold to do it! You also may want to put a wire shield around the plant base. Quarter-inch hardware cloth works quite well.

May Be a Fire Hazard

Some mulches, such as very dry hay, straw, and sawdust, can catch fire easily.

Solution. Be careful around these mulches. Don't smoke near them, and during extraordinarily dry periods water them occasionally. If you live in an area prone to wildfires, consider using a less flammable mulch, such as stone, in landscape beds.

A Few Definitions

Here seems a good place to explain some terms. These are not meant to be strict, inflexible definitions. They are offered simply as working definitions to describe what is meant when a particular word is used in this book.

Mulch can be any material applied to the soil surface to retain moisture, insulate and stabilize the soil, protect plants, and control weeds. A properly functioning mulch has two basic properties. Good mulch should be (1) light and open enough to permit the passage of water and air and (2) dense enough to inhibit or even choke weed growth.

Mulches can be divided into two fundamental categories:

* Organic mulches are like unfinished compost. Anything that will biodegrade (rot) can be used as organic mulch. The most common organic mulches are shredded or chipped bark, leaves and leaf mold, hay, straw, and grass clippings.

* Synthetic mulches, sometimes called inert or artificial mulches, don't begin as plant material. They include colored plastics and geotextile landscape fabric, made from polypropylene or polyester.

* Here are a few other terms associated with mulching that are sometimes bandied about:

* Summer mulches, or growing mulches, are applied in the spring after the soil starts to warm. Throughout the summer they insulate the soil, inhibit weed growth, retain moisture, and control erosion. Both organic and synthetic mulches fall into this category.

* Winter mulches are used around woody plants and perennials to insulate against freeze/thaw damage to plants' crowns and roots. Winter mulch is applied in late fall after the soil has cooled, preferably following a hard frost. Winter mulches prevent the soil temperature from jumping up and down, which heaves plants out of the ground. Ordinarily, winter mulches are organic, but geotextiles may provide adequate winter protection.

* Living mulches are low-growing, shallow-rooted, ever-spreading ground cover plants such as thyme or pachysandra. These mulch plants are attractive and commonly used in border flower beds, ornamental plantings, and rock gardens.

* Permanent mulches are usually made up of nondisintegrating materials. Permanent mulches such as crushed stone and gravel are useful, particularly in perennial beds, around trees and shrubs, and on soil not likely to be tilled or cultivated.

* Green manures, or cover crops, are basically plants like oats, alfalfa, and buckwheat that meet the definition of mulch. They afford fine winter and erosion protection and have the added advantage of attracting beneficial insects during the growing season. They can be either tilled under or harvested and applied as mulch in another part of the garden. Cover crops are used mostly in vegetable gardens or with small fruit plantings.

CHAPTER 2

PART TWO

Types of Mulch

Depending on the material, mulch can be decorative, functional, or both. Biodegradable organic mulches conserve soil moisture and, in varying degrees, add nutrients to the soil. Stones and most inorganic mulches don't improve a soil's health or water retention. Organic and inorganic mulches both largely provide weed and erosion control. Following are descriptions of many common and uncommon mulches.

Bark and Wood Products

Bark and wood products, scavenged or purchased, have long been used as landscape and garden mulches.

Bark

Uses. Decorative and functional.

What it is. Bark is probably the most common and versatile of the landscape mulches and comes in a variety of shapes, sizes, colors, and textures. Recommended varieties of bark and wood mulch are listed in Which Wood Is That?. Bark mulch comes in several sizes (from ¼ inch to 3 inches in diameter) and forms (nuggets, chips, shredded). Bark mulch is sold in bags or in bulk by the cubic yard.

Bark choices.Bark mulch is readily available in several attractive forms, such as nuggets, chips, and shredded.

How to use it. Prepare the garden bed, install plants, and water thoroughly and deeply. Then apply mulch like a blanket over the plant's existing or potential roots. Cover the entire bed evenly with a mulch layer 2 to 4 inches thick. Because mulch against a plant stem or tree trunk will invite rot and insects, keep mulch at least 6 inches away from the base of a woody shrub or a tree trunk.

Pros. Readily available in many forms. Attractive. Because it decomposes slowly, bark mulch is less hospitable to artillery fungus (see What's Growing in My Wood Mulch?).

(Continues…)

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Excerpted from "How To Mulch"
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Copyright © 2015 Storey Publishing.
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