Mulch Textbook

Mulching:

Mulching is one of the simplest and most beneficial practices you can use in dryland farming. Mulch is simply a protective layer of a material that is spread on top of the soil. Mulches can either be living -such as grass clippings, straw, bark chips, and similar materials- or non living -such as stones, brick chips. Both live and stone mulches have numerous benefits. Though for the purpose of dryland farming we will be dealing with living... or crop waste mulching.

Benefits of Mulching: a. protects the soil from erosion b. reduces compaction from the impact of heavy rains c. conserves moisture, reducing the need for frequent watering d. maintains a more even soil temperature e. prevents weed growth f. keeps fruits and vegetables clean

Crop waste 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. Crop waste is a source of plant nutrients and provides an ideal environment for earthworms and other beneficial soil organisms.

While stone and other non-living mulches have their place in certain circumstances, they lack the soil improving properties of crop waste mulches. Stone mulches, because of their permanence, are difficult to work with, and difficult to remove if you decide to change your farming plans at later date.

Mulch materials: Grass clippings make excellent mulch. While not pleasing to the eye, they work wonderfully with vegetable farming. The fine texture allows them to be spread easily even around small plants. Though impractical, paper waste 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 absorbent spongy structure, much like the forest floors. 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.

Hay and straw work well in the vegetable farming, although they may harbor weed seeds. Seaplant mulch, ground corn cobs, and pine needles, also makes excellent mulch. Although pine needles tend to increase sourness of the soil so they work best around certain plants that love that kind of soil condition, like berries.

When to apply mulch: Time 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 farm or herb 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 growth, 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 rapid fluctuations in soil temperature and reduces the chance of heaving.

Applying mulch:

1. Begin by asking yourself the following questions. a. What do I hope to achieve by mulching? - Weed control? - Moisture retention? - Soil improvement? - Temperature control? b. How large is the area to be mulched? c. How much mulch will I need to cover the area? Mulch should be measured in cubic feet. As an example, if you have an area 10 feet by 10 feet and you wish to apply 3 inches of mulch, you would need 25 cubic feet of mulch. 2. Determine what mulch material to use and purchase or accumulate what you need. a. Leaves -Collect leaves in the fall. -Chop leaves into small pieces. Whole leaves tend to compact if wet or blow away if dry. Chopping will reduce the volume and facilitate composting -Compost leaves over winter. Some observations indicate that freshly chopped leaves may inhibit the growth of certain crops. Therefore, it may be advisable to compost the leaves over winter before spreading them. b. Grass clippings -Spread them immediately to avoid heating and rotting.

General Guidelines: 1. Do not apply mulch directly in contact with plants. Leave an inch or so of space next to plants to help prevent diseases flourishing from excessive humidity. 2. Remove weeds before spreading mulch. Bark mulch/2-4 inches: Smaller chips are easier to spread, especially around small plants. Excellent for use around trees, shrubs, and perennials. When spreading mulch around trees, keep the mulch an inch or two away from the trunk. Wood chips/2-4 inches: Similar to bark mulch. If using fresh wood chips that are mixed with a lot of leaves, composting is beneficial. Grass clippings/2-3 inches: Thicker layers tend to compact and rot, becoming quite slimy and smelly. Add additional layers as clippings decompose. Compost/3-4 inches: Excellent material for enriching soil.