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MulchingMulching enriches and protects soil, helping provide a better growing environment. In Your BackyardMulching is one of the simplest and most beneficial practices you can use in the garden. Mulch is simply a protective layer of a material that is spread on top of the soil. Mulches can either be organic -- such as grass clippings, straw, bark chips, and similar materials -- or inorganic -- such as stones, brick chips, and plastic. Both organic and inorganic mulches have numerous benefits. Mulch
Organic mulches also improve the condition of the soil. As these mulches slowly decompose, they provide organic matter which helps keep the soil loose. This improves root growth, increases the infiltration of water, and also improves the water-holding capacity of the soil. Organic matter is a source of plant nutrients and provides an ideal environment for earthworms and other beneficial soil organisms. While inorganic mulches have their place in certain landscapes, they lack the soil improving properties of organic mulches. Inorganic mulches, because of their permanence, may be difficult to remove if you decide to change your garden plans at a later date. Therefore, this tip sheet is limited to the use of organic mulches. Mulch MaterialsYou can find mulch materials in your own yard! Lawn clippings make excellent mulch. While not particularly attractive for a flower bed, they work wonderfully in the vegetable garden. The fine texture allows them to be spread easily even around small plants. However, grass clippings are becoming scarce because of the increased popularity of mulching lawnmowers that provide many of the same benefits of mulching to lawns. Newspaper, as a mulch, works especially well to control weeds. Leaves are another readily available material to use as mulch. Leaf mold, or the decomposed remains of leaves, gives the forest floor its absorbent spongy structure. Compost makes a wonderful mulch if you have a large supply. Compost not only improves the soil structure but provides an excellent source of plant nutrients. Bark chips and composted bark mulch are available at garden centers. These make a neat finish to the garden bed and will eventually improve the condition of the soil. These may last for one to three years or more depending on the size of the chips or how well composed the bark mulch is. Smaller chips tend to be easier to spread, especially around small plants. Depending on where you live, numerous other materials make excellent mulches. Hay and straw work well in the vegetable garden, although they may harbor weed seeds. Seaweed mulch, ground corn cobs, and pine needles can also be used. Pine needles tend to increase the acidity of the soil so they work best around acid-loving plants such as rhododendrons and blueberries. When to Apply MulchTime of application depends on what you hope to achieve by mulching. Mulches, by providing an insulating barrier between the soil and the air, moderate the soil temperature. This means that a mulched soil in the summer will be cooler than an adjacent unmulched soil; while in the winter, the mulched soil may not freeze as deeply. However, since mulch acts as an insulating layer, mulched soils tend to warm up more slowly in the spring and cool down more slowly in the fall than unmulched soils. If you are using mulches in your vegetable garden or flower garden, it is best to apply them after the soil has warmed up in the spring. Cool, wet soils tend to slow seed germination and increase the decay of seeds and seedlings. If adding additional layers of mulch to existing perennial beds, wait until the soil has warmed completely. Mulches used to help moderate winter temperatures can be applied late in the fall after the ground has frozen but before the coldest temperatures arrive. Applying mulches before the ground has frozen may attract rodents looking for a warm over-wintering site. Delayed applications of mulch should prevent this problem as, hopefully, the creatures would already have found some other place to nest! Mulches used to protect plants over winter should be loose material such as straw, hay, or pine boughs that will help insulate the plants without compacting under the weight of snow and ice. One of the benefits from winter applications of mulch is the reduction in the freezing and thawing of the soil in the late winter and early spring. These repeated cycles of freezing at night and then thawing in the warmth of the sun cause many small or shallow rooted plants to be heaved out of the soil. This leaves their root systems exposed and results in injury or death. Mulching helps prevent the rapid fluctuations in soil temperature and reduces the chances of heaving. Applying Mulch
General Guidelines
Bark mulch and wood chips are sometimes used with landscape fabric or plastic. The fabric or plastic is laid on top of the soil and then covered with a layer of bark chips. A caution to this practice: while initially the plastic or fabric may provide additional protection against weeds, as the mulch breaks down, weeds will start to grow in the mulch itself. The barrier between the soil and the mulch also prevents any improvement in the soil condition and makes planting additional plants more difficult. For Sources of MulchCheck under mulches or garden centers or nurseries in the Yellow Pages. Your community may also have wood chips from the removal of street trees that are available free to residents. On the FarmFarmers use mulches in many ways. Conservation tillage is a common practice that creates a mulch on the soil surface. Unlike the once common practice of plowing all crop residue into the soil, conservation tillage leaves the crop residue on top of the soil. These pieces of corn stalk, straw, or bean stems help protect the soil against wind and water erosion. Corn crops harvested for the grain return large amounts of residue to the soil surface and are more effective in preventing soil erosion than crops with less residue such as soybeans. Mulching is a common practice among strawberry growers in northern climates. In this situation, mulch is used to protect the crop during the winter and to help prevent early blooming of the plants. Plants that bloom too early are more likely to be damaged by spring frosts. The mulch also helps keep the berries cleaner, protecting them from soil splashing on them in the rain. Inorganic mulches are also widely used in commercial agriculture. Clear plastic mulch can be particularly beneficial in giving warm season crops a head start. The clear plastic acts as a mini-greenhouse, warming the soil underneath it. Particularly where early sweet corn brings a premium price, this practice can give a grower a couple of weeks head start. Also, research is showing that leaving crop residues helps hold carbon in the soil and aids in reducing greenhouse gases. More About Backyard Conservation |
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