Why Should I Mulch?

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Weed growth in and around your ornamental borders and gardens can be a major problem. Mulching is a very effective way to help prevent weeds for various reasons such as excluding light from the soil surface, by not giving young weeds a firm material to build a root system in, etc. As well as preventing weed growth, organic mulches can help add nutrients to your soil as they decay. A quality fabric weed barrier is often used between the soil and mulch to further inhibit weed growth while allowing water and nutrients into the soil. A layer of 2-4 inches is recommended for a good effective covering, depending upon preference and type of mulch used. Done right, mulching can eliminate or greatly reduce trimming and weed eating in your lawn or garden, as well as provide a very attractive ground covering.
 

	Iowa DNR Mulch Resource Guide:
	Iowa DNR Benefits of Mulch Iowa DNR Mulch Benefits Brochure

How Do I Mulch?

The area should be cleared of all weeds, leaves and grass. If you are preparing an area on an established lawn, make sure you strip the sod completely. Edge around the entire border of your landscape area, which is easily done with a flat shovel or a power edger. If you are replenishing the mulch on an existing mulched area, be sure to loosen up the old mulch. Using your hands to spread the mulch produces the best results. Use a thickness of 2 to 4 inches, not allowing the mulch to make direct contact with plants. This avoids disease problems. Also, keep it from contacting nearby wooden structures in case of termites. When finished, the mulch should be watered down to put moisture in it and to help settle it into place.
 

Before You Mulch:

Mulch is the icing to the cake, there is some work to be done before you spread your mulch. Follow the steps below to achieve great results.

1. Kill Weeds – it is a good idea to spray all weeds with Round-Up or another weed killer 1 to 2 weeks prior to mulching. This will allow the weeds to completely die. Dead weeds are the best weeds to pull!
    
2. Trim Trees and Bushes – because of the debris produced, it is recommended that you trim your trees and bushes prior to mulching.
    
3. Clean Out Your Beds – clean out all dead leaves, weeds and trimmings with a rake. An adjustable rake works best.
    
4. Cultivate – after your beds have been cleaned, cultivate any compacted soil or mulch. A roto-tiller or hand cultivator will do the job. Cultivating will allow moisture and air to pass through the mulch easier.
    
5. Edge Your Beds – creating a clean edge really enhances your landscape and gives it a professional look. An edging shovel or power edger can be used to create your edge. Try using your garden hose as a guide to create nice flowing curves.
    
6. Rake Smooth – using a stiff rake, such as a mud rake, smooth out all the surfaces to be mulched. Otherwise, your mulch will look lumpy.
    
7. Apply a Pre-Emergent – now is the time to apply one such as Preen, to prevent germination of weed seeds. A second application, after the mulch has been installed, can add protection from weed seeds that may germinate in the mulch.
    
8. It’s Time To Mulch – using your hands or a Mulch Rake, apply new mulch over the existing cultivated mulch or soil to a desired thickness. When complete, water to moisturize mulch and settle it into place.
    
9. Mulch Maintenance – after a month or so, check your mulch for compaction. If compacted, use a Mulch Rake to loosen it. This will allow water and air to pass, which helps prevent the growth of fungus and restores appearance.
    
10. Fungus – if present, remove it with the surrounding mulch. Rake existing mulch to cover the area, then water thoroughly. Fungus is a sure sign that your mulch has compacted and your beds have dehydrated, cultivation and watering may be necessary.
     

Mulch Facts:

Mulch Is More Than Decorative

Mulch retains moisture, retards weeds, provides nutrients, controls erosion and insulates the soil protecting plants from extreme temperature variations.

Too Much Mulch Is Harmful

Mulch should be applied 2-4 inches thick to provide blanket after settling . Building a volcano around a tree is an example of excessive mulching and it will cause more harm than good. It should never be placed against the bark of your woody plants, such as bushes and trees, it could cause disease. Mulches, especially hardwood mulch, compacts after a few rains. This compaction causes a dry condition under the mulch, which starves the soil and plants of air and water, promoting the growth of fungus and can cause disease to your plants. We recommend occasionally aerating or cultivating to reduce compaction.

Mulch Can Be Toxic

Toxic mulch, also known as “sour mulch” mainly occurs with hardwood bark mulches. This occurs when a mulch producer improperly composts the mulch. Methane, alcohol, ammonia and hydrogen sulfide gases will build to toxic levels due to the lack of oxygen and too much moisture. “Sour Mulch” can kill your plants! Be aware and recognize it, the mulch will have a vinegar or ammonia smell. If the mulch has already been applied, water the mulch thoroughly.

All Mulches Are Not The Same

There are many mulch producers across the country and around the world. Each sources their own raw materials and implements their own production methods. Due to these factors, you will find an enormous selection of mulches across the country. The most common types in the United States are hardwood bark, cypress, pine and cedar. Hardwood and pine mulches will break down and release nutrients into your soil. Cypress and cedar mulches break down extremely slow. Therefore, their benefits are primarily for decorative use, holding moisture, controlling erosion and retarding weed growth. Pine bark mulch holds up the longest and is best for your plants and soil.
 

Winterizing With Mulches

Iowa’s relatively warm days and cold nights, extreme temperature fluctuations and drying winds can wreak havoc with many of our commonly planted perennials.

Generally, after the first hard frost, the foliage of most perennials starts to die and wither. There are two philosophies on when to remove the dead foliage. One approach is to immediately remove the dead foliage. Many perennials will suffer no harm as a result, as long as you exercise great care when applying mulch. The other approach is waiting until spring to remove dead foliage. Always remove diseased foliage to discourage the spread of leaf-spot diseases and fungal problems.

Dehydration is a common problem when snowless winters occur. A layer of mulch several inches thick helps retain soil moisture. This mulch should be coarse and loose to permit air movement to roots. Root tissues continue to metabolize in the winter and requires oxygen for this process to take place. Reduced soil oxygen level increases the aggressiveness of many soil pathogens. Mulches which pack down should be avoided.

Watering at least monthly under dry winter conditions recharges the soil profile with moisture critical to plant survival.

Whether you decide to remove dead foliage in the fall or wait until spring, mulches provide the best protection for your perennials. Many types of mulches are available, and no matter which you choose, there are a few guidelines you should follow.
Mulches do a better job of insulating plants when space is allowed for air to circulate. Mulch that packs down to a dense mass during winter can cause mildews and molds to form. A good organic compost used as mulch is also effective and can be used as a soil amendment in the spring.

Established perennials and bulbs benefit from mulches that are applied after the ground freezes, because mulches don't allow soil temperatures to fluctuate as much throughout the winter.

Mulch should not be removed too early in spring or plants will begin to grow too early. Plants located on the south side of a building or wall will emerge sooner than those in other areas, but may be subject to spring frost damage. Some perennials can be damaged by drying winter winds and western sun. Fencing can be used to effectively to protect plantings.

	Iowa DNR Mulch Resource Guide:
	Iowa DNR Benefits of Mulch Iowa DNR Mulch Benefits Brochure

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Mulch Mart LLC. 600 Hwy 6. P.O. Box 138, Waukee, IA 50263 | 515.978.6852